|
* [[Utente:BlackPanther2013/Sandbox/parchi]]
{{nota disambigua||[[Giraffa (disambigua)]]|Giraffa}}
* [[Utente:BlackPanther2013/Sandbox/citelli]]
* [[Utente:BlackPanther2013/Sandbox/rapaci]]
* [[Utente:BlackPanther2013/Sandbox/kakapo]]
* [[Utente:BlackPanther2013/Sandbox/Mata Atlantica]]
* [[Utente:BlackPanther2013/Sandbox/1.0]]
* [[Utente:BlackPanther2013/Sandbox/1]]
* [[Utente:BlackPanther2013/Sandbox/2]]
* [[Utente:BlackPanther2013/Sandbox/Global200]]
* [[Utente:BlackPanther2013/Sandbox/Caracal]]
* [[Utente:BlackPanther2013/Sandbox/felini]]
* [[Utente:BlackPanther2013/Sandbox/citelli]]
* [[Utente:BlackPanther2013/Sandbox/O.v.]]
* [[Utente:BlackPanther2013/Sandbox/S.m.]]
* [[Utente:BlackPanther2013/Sandbox/elefanti]]
{{Tassobox
|nome=Citello della Columbia
|nome=Giraffa<ref name=msw3>{{MSW3|id=14200476}}</ref>
|statocons=LC
|statocons_versione=iucn iucn33.1
|statocons_ref=<ref name="IUCN>{{IUCN|summ=9194|autore=Fennessy, J. & Brown, D. 2010}}<"/ref>
|immagine=[[File:Giraffe_Mikumi_National_ParkUrocitellus columbianus Alberta Martybugs.jpg|250px230px]]
|didascalia=
|didascalia=Una [[Giraffa camelopardalis tippelskirchi|giraffa masai]] nel [[parco nazionale di Mikumi]] ([[Tanzania]])
<!-- CLASSIFICAZIONE -->
|dominio=[[Eukaryota]]
|regno=[[Animalia]]
|sottoregno=
|superdivisione=
|divisione=
|sottodivisione=
|superphylum=
|phylum=[[Chordata]]
|infraclasse=
|superordine=
|ordine=[[ArtiodactylaRodentia]]
|sottordine=[[Sciuromorpha]]
|infraordine=
|superfamiglia=
|famiglia=[[GiraffidaeSciuridae]]
|sottofamiglia=[[Xerinae]]
|tribù=[[Marmotini]]
|sottotribù=
|genere='''Giraffa'''[[Urocitellus]]
|genereautore=[[Mathurin Jacques Brisson|Brisson]], [[1762]]
|sottogenere=
|specie='''GU. camelopardaliscolumbianus'''
|sottospecie=
<!-- NOMENCLATURA BINOMIALE: -->
|biautore=([[Carl von Linné|Linnaeus]]
|biautore=([[George Ord|Ord]]
|binome=Giraffa camelopardalis
|binome=Urocitellus columbianus
|bidata=[[1758]])
|bidata=1815)
<!-- NOMENCLATURA TRINOMIALE: -->
|triautore=
|trinome=
|tridata=
<!-- ALTRO: -->
|sinonimi?=
|sinonimi=''Spermophilus columbianus''
|nomicomuni=
|suddivisione=[[Areale]]
|suddivisione_testo=[[File:Giraffa_camelopardalis_distributionUrocitellus columbianus species distribution map.svg|250px230px]]
}}
Il '''citello della Columbia''' ('''''Urocitellus columbianus''''' [{{zoo|[[George Ord|Ord]]|11815}}]) è una specie di [[Rodentia|roditore]] diffusa in alcune regioni del [[Canada]] e degli [[Stati Uniti d'America|Stati Uniti]] nord-occidentali. È il secondo membro per dimensioni del genere ''[[Urocitellus]]'', che fa parte della tribù [[Marmotini]], insieme a marmotte, tamia, cani della prateria e altri scoiattoli di terra [[Olartico|olartici]]. Questi citelli hanno una corporatura robusta, con pelliccia corta e densa, tipicamente fulva sul dorso del naso. Gli incontri sociali talvolta iniziano con un comportamento simile al «baciarsi», mentre l'attività più comune quando si trovano in superficie è restare eretti in posizione vigile. Vivono in ambienti montuosi e altipiani delle regioni settentrionali, e vanno in letargo per 8-9 mesi l'anno, rifugiandosi in tane che possono essere utilizzate per molti anni consecutivi. Al momento della riemersione in primavera, appaiono notevolmente emaciati. Il citello della Columbia attirò per la prima volta l'attenzione della comunità scientifica grazie agli scritti prodotti da [[Spedizione di Lewis e Clark|Lewis e Clark]], mentre nel XXI secolo la genetica molecolare ne ha ulteriormente chiarito le relazioni con altre specie strettamente affini.
La '''giraffa''' ('''''Giraffa camelopardalis''''' <span style="font-variant: small-caps">[[Carl von Linné|Linnaeus]], [[1758]]</span>) è un [[Mammalia|mammifero]] [[Artiodactyla|artiodattilo]] africano; è l'animale terrestre [[Neontologia|vivente]] più alto, nonché il [[Ruminantia|ruminante]] di maggiori dimensioni. Il suo [[Nomenclatura binomiale|nome specifico]] si riferisce alla struttura corporea simile a quella del [[Camelus|cammello]] e alla colorazione simile a quella del [[Panthera pardus|leopardo]]. Le sue caratteristiche principali più appariscenti sono il collo e le zampe estremamente lunghi, gli [[ossiconi]] simili a corna e la peculiare colorazione del manto. Viene classificata all'interno della [[Famiglia (tassonomia)|famiglia]] dei [[Giraffidae|Giraffidi]], assieme all'unico suo stretto parente giunto fino a oggi, l'[[Okapia johnstoni|okapi]]. Le sue nove sottospecie si differenziano per la colorazione del mantello.
== Descrizioni ==
L'areale frammentato della giraffa si estende dal [[Ciad]] al nord al [[Sudafrica]] a sud, e dal [[Niger]] a ovest alla [[Somalia]] a est. Le giraffe generalmente vivono in [[Savana|savane]], [[Prateria|distese erbose]] e [[Bosco|aree boschive]] aperte. Loro fonte di cibo principale sono le foglie di [[acacia]], che brucano ad altezze che la maggior parte degli altri erbivori non può raggiungere. Le giraffe costituiscono preda dei [[Panthera leo|leoni]]; i piccoli sono oggetto di caccia anche di [[Panthera pardus|leopardi]], [[Crocuta crocuta|iene macchiate]] e [[Lycaon pictus|licaoni]]. Tra le giraffe adulte non vi sono stretti legami sociali, sebbene possano radunarsi in aggregazioni labili nel caso più esemplari si dirigano nella stessa direzione. I maschi stabiliscono gerarchie sociali attraverso il «necking», vale a dire combattimenti che prevedono l'utilizzo del collo come arma di offesa. I maschi dominanti ottengono il privilegio di accoppiarsi con le femmine, sulle quali grave l'intera responsabilità dell'allevamento dei piccoli.
Il citello della Columbia è tra i membri più grandi del suo genere, superato solo dal [[Urocitellus parryii|citello di Parry]].<ref name=r2>{{cita|Elliott e Flinders, 1991|p. 1}}.</ref> Ha una struttura corporea robusta e compatta, con una lunghezza totale di 325-410 mm, di cui 80-116 mm costituiti dalla coda. Le zampe posteriori misurano tra i 47 e i 57 mm, mentre l'orecchio è lungo tra i 16 e i 22,5 mm.
La pelliccia è densa e relativamente corta. Sul muso è presente una tipica colorazione bronzea che attraversa il dorso del naso. La pelliccia lungo dorso, zampe e piedi assume tonalità cannella, più scura vicino al corpo. Attorno agli occhi vi è un anello di pelliccia beige chiaro o fulvo chiaro. Sul collo, ai lati delle guance, il pelo è grigio. I fianchi possono essere beige chiaro o grigiastri. La coda è più scura, con sottopelo scuro e alcune macchie beige più chiare sopra, mentre inferiormente varia dal grigio scuro al bianco grigiastro.<ref name=r2/> La [[Muta (biologia)|muta]] avviene diffusamente, senza linee di separazione nette.<ref name=r2/>
Per il suo aspetto peculiare, la giraffa è stata oggetto di attrazione per varie culture, sia antiche che moderne, ed è stata spesso rappresentata in dipinti, libri e cartoni animati. Viene classificata dall'[[Unione Internazionale per la Conservazione della Natura]] come specie «a rischio minimo», ma è scomparsa da molte zone del suo areale originario e alcune sottospecie sono [[Specie a rischio|in pericolo di estinzione]]. Ciononostante, le giraffe sono ancora diffuse in numerosi [[Parco nazionale|parchi nazionali]] e [[Riserva di caccia|riserve di caccia]].
[[File:Columbian Ground Squirrel Roger's Pass.jpg|thumb|left|Un esemplare all'ingresso della tana]]
Sono state descritte due sottospecie, con alcune differenze di aspetto. Rispetto a ''U. c. columbianus'', la popolazione ''U. c. ruficaudus'' presenta una coda più rossiccia e meno grigia sulla superficie superiore. I lati del muso e della gola hanno anch'essi una tonalità rossastra più accentuata. Anche zampe e piedi risultano più scuri.<ref name=r2/> Il cranio di ''U. c. ruficaudus'' è più largo, con arcate zigomatiche più robuste.<ref name=r2/>
Sono stati osservati diversi esemplari [[Albinismo|albini]]. Un citello albino venne catturato vivo da uno studente vicino a Pullman, Washington, nel 1932, in un campo di erba medica. Questo animale aveva pelo bianco e occhi rosa. Uno zoologo dichiarò l'intenzione di mantenerlo vivo per studiare i modelli di ereditarietà genetica.<ref name=r3>{{cita|Svihla, 1932}}.</ref> L'anno successivo, lo stesso studioso riferì di aver trovato altri tre giovani albini nella medesima area.<ref name=r4>{{cita|Svihla, 1933}}.</ref> Circa 30 anni prima erano state raccolte altre due pelli di esemplari albini, sempre nei pressi di Pullman. Si ipotizzò che il carattere recessivo dell'albinismo persistesse localmente, manifestandosi a intervalli sporadici.<ref name=r3/>
==Etimologia==
L'origine del nome «giraffa» viene fatta risalire alla parola [[Lingua araba|araba]] ''zarafah'' (زرافة), forse a sua volta derivata da una lingua africana<ref name=OED/>. Il nome viene tradotto come «[colei che] cammina velocemente»<ref name=kingdon/>. Nella [[lingua inglese media]] l'animale era noto anche come ''jarraf'', ''ziraph'' e ''gerfauntz''<ref name=OED/>. La parola probabilmente deriva dal nome [[Lingua somala|somalo]] dell'animale, ''geri''<ref>{{cita libro|autore=C. Peust|anno=2009|titolo=Semito-Hamitic Festschrift for A. B. Dolgopolsky and H. Jungraithmayr|editore=Reimer|paine=257-60|isbn=3-496-02810-6}}</ref>. La forma [[Lingua italiana|italiana]] ''giraffa'' risale agli anni '90 del XVI secolo<ref name=OED>{{cita web|url=http://etymonline.com/?term=giraffe|titolo=Giraffe|editore=Online Etymology Dictionary|accesso=1 November 2011}}</ref>. L'attuale forma inglese ''giraffe'' si sviluppò intorno al 1600 a partire dal [[Lingua francese|francese]] ''girafe''<ref name=OED/>.
== Distribuzione e habitat ==
Il nome specifico ''camelopardalis'' è di origine [[Lingua latina|latina]]<ref>{{cita web|url=http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dcamelopardalis|titolo=camelopardalis|editore=A Latin Dictionary, Perseus Digital Library|accesso=23 novembre 2011}}</ref>. «Camelopard» è un arcaico nome inglese della giraffa derivato dalle parole [[Lingua greca antica|greche antiche]] che indicavano il cammello e il leopardo, animali a cui la gireffa ritenevano somigliasse<ref>{{cita web|titolo=Definition of CAMELOPARD|url=http://www.merriam-webster.com/dictionary/camelopard|sito=m-w.com|editore=Encyclopædia Britannica: Merriam-Webster|acceso=3 settembre 2014}}</ref><ref>{{cita web|titolo=Definition of camelopard|url=http://medieval_terms.enacademic.com/615/Camelopard|editore=Dictionary of Medieval Terms and Phrases|accesso=3 settembre 2014}}</ref>.
Il citello della Columbia si trova nelle regioni occidentali del Nord America.<ref name="IUCN"/> È presente lungo le [[Montagne Rocciose]], a partire dal Canada occidentale, nell'Alberta occidentale e nel sud-est della Columbia Britannica.<ref name=r2/> Si trova inoltre nelle regioni occidentali del Montana, attraversando l'Idaho centrale e raggiungendo le aree settentrionali e orientali dello stato di [[Washington (stato)|Washington]].<ref name="IUCN"/> È presente anche nelle pianure della parte orientale dello stato di Washington. In Oregon, si trova nelle zone montuose nella parte centro-orientale dello stato. Questi animali vivono ad altitudini comprese tra i 210 e i 2.440 metri.<ref name=r2/>
La documentazione fossile nota del citello della Columbia comprende esemplari recuperati dal sito fossile di Wasden (Owl Cave), nella [[contea di Bonneville]], Idaho.<ref name=r5>{{cita|Kurtén e Anderson, 1980|p. 215}}.</ref> I fossili provenienti da questo sito risalgono al tardo [[Pleistocene]] (Rancholabreano).<ref name=r6>{{cita|Kurtén e Anderson, 1980|p. 62}}.</ref> Il sito si trova ad un'altitudine di 1.584 metri.<ref name=r6/> I fossili di piccoli mammiferi rinvenuti in questo sito sono principalmente attribuiti alla predazione da parte di gufi.<ref name=r7>{{cita|Kurtén e Anderson, 1980|pp. 62-63}}.</ref>
''Kameelperd'' è anche il nome della specie in [[lingua afrikaans]]<ref name=walker>{{cita libro|autore=C. Walker|anno=1997|titolo=Signs of the Wild|editore=Struik|pagina=142|isbn=1-86825-896-3}}</ref>. Tra gli altri nomi africani della giraffa ricordiamo ''ekorii'' (ateso), ''kanyiet'' (elgon), ''nduida'' ([[Lingua gikuyu|gikuyu]]), ''tiga'' (kalenjin e luo), ''ndwiya'' ([[Lingua kamba|kamba]]), ''nudululu'' (kihehe), ''ntegha'' (kinyaturu), ''ondere'' (lugbara), ''etiika'' (luhya), ''kuri'' (ma'di), ''oloodo-kirragata'' o ''olchangito-oodo'' (maasai), ''lenywa'' (meru), ''hori'' (pare), ''lment'' (samburu) e ''twiga'' ([[Lingua swahili|swahili]] e altre) nell'Africa orientale<ref name=Kingdon1988/>; e ''tutwa'' ([[Lingua lozi|lozi]]), ''nthutlwa'' ([[Lingua tsonga|shangaan]]), ''indlulamitsi'' ([[Lingua swati|siswati]]), ''thutlwa'' ([[Lingua tswana|sotho]]), ''thuda'' ([[Lingua venda|venda]]) e ''ndlulamithi'' ([[Lingua zulu|zulu]]) in quella meridionale<ref name=walker/>.
La distribuzione del citello della Columbia in Oregon è stata valutata sulla base di esemplari raccolti in 71 località. Oltre il 98% degli esemplari proveniva dall'ecoregione delle [[Foreste delle Blue Mountains|Blue Mountains]],<ref name=r8>{{cita|Verts e Carraway, 1998|p. 24}}.</ref> che include le catene montuose [[Wallowa Mountains|Wallowa]] e [[Blue Mountains (Nord-ovest Pacifico)|Blue Moutains]].<ref name=r9>{{cita|Verts e Carraway, 1998|p. 188}}.</ref> Gli esemplari restanti provengono dagli altipiani di Owyhee.<ref name=r8/>
==Taxonomy and evolution==
[[File:Shansitherium tafeli Beijing.jpg|thumb|left|Mounted ''[[Shansitherium]]'' skeleton from the [[Beijing Museum of Natural History]]]]
The giraffe belongs to the suborder [[Ruminantia]]. Many Ruminantia have been described from the mid-Eocene in Central Asia, Southeast Asia, and North America. The ecological conditions during this period may have facilitated their rapid dispersal.<ref name=Mitchell20003 /> The giraffe is one of only two living species of the family [[Giraffidae]], the other being the [[okapi]]. The family was once much more extensive, with over 10 fossil [[Genus|genera]] described. Their closest known relatives are the extinct [[Climacoceratidae|climacocerids]]. They, together with the family [[Antilocapridae]] (whose only extant species is the [[pronghorn]]), belong to the superfamily [[Giraffoidea]]. These animals evolved from the extinct family [[Palaeomerycidae]] 8 million years ago (mya) in south-central Europe during the Miocene epoch.<ref name="Mitchell20003">{{cite journal | author = Mitchell, G.; Skinner, J. D. | year = 2003 | title = On the origin, evolution and phylogeny of giraffes ''Giraffa camelopardalis'' | journal = Transactions of the Royal Society of South Africa | volume = 58 | issue = 1| pages = 51–73| doi = 10.1080/00359190309519935| url = http://tsjok45.files.wordpress.com/2012/12/giraffeevolution.pdf}}</ref>
== Biologia ==
While some ancient giraffids, such as ''[[Sivatherium]]'', had massive bodies, others, such as ''[[Giraffokeryx]]'', ''[[Palaeotragus]]'' (possible ancestor of the okapi), ''[[Samotherium]]'', and ''[[Bohlinia]]'', were more elongated.<ref name="Mitchell20003"/> ''Bohlinia'' entered China and northern India in response to climate change. From here, the genus ''[[Giraffa]]'' evolved and, around 7 mya, entered Africa. Further climate changes caused the extinction of the Asian giraffes, while the African ones survived and radiated into several new species. ''G. camelopardalis'' arose around 1 mya in eastern Africa during the [[Pleistocene]].<ref name="Mitchell20003"/> Some biologists suggest the modern giraffe descended from ''[[Giraffa jumae|G. jumae]]'';<ref name=sim1996/> others find ''[[Giraffa gracilis|G. gracilis]]'' a more likely candidate.<ref name="Mitchell20003"/> The main driver for the evolution of the giraffes is believed to have been the change from extensive forests to more open habitats, which began 8 mya.<ref name="Mitchell20003"/> Some researchers have hypothesized that this new habitat coupled with a different diet, including ''[[Acacia]]'', may have exposed giraffe ancestors to toxins that caused higher mutation rates and a higher rate of evolution.<ref name="bada"/>
[[File:Urocitellus columbianus burrow diagram.svg|thumb|left|Schema della tana del citello della Columbia]]
In Alberta, i citelli della Columbia restano in letargo circa 250 giorni all'anno, con solo 69-94 giorni di attività osservati. Il periodo di attività varia a seconda del clima locale, così come delle differenze comportamentali tra individui di diverso sesso ed età.<ref name=r10>{{cita|Verts e Carraway, 1998|p. 189}}.</ref> Ogni gruppo di sesso ed età va in letargo a profondità differenti nel terreno e inizia il letargo quando la temperatura del suolo nelle rispettive tane raggiunge il valore massimo.<ref>{{cita pubblicazione | autore=P. J. Young | data=luglio 1990 | titolo=Hibernating patterns of free-ranging Columbian ground squirrels | url=http://link.springer.com/10.1007/BF00317201 | rivista=Oecologia | volume=83 | numero=4 | pp=504-511 | doi=10.1007/BF00317201 | pmid=28313184 | bibcode=1990Oecol..83..504Y | issn=0029-8549}}</ref> Durante il letargo, i citelli assumono una posizione verticale, rannicchiati in una palla compatta. La loro temperatura corporea cala notevolmente, il battito cardiaco rallenta, e la respirazione diviene quasi impercettibile.<ref name=r12>{{cita|Shaw, 1918}}.</ref> Il primo gruppo a riemergere in superficie è quello dei maschi adulti, probabilmente a causa della necessità di rigenerare i testicoli per la stagione riproduttiva, dato che in molti citelli è stato osservato che durante il letargo i testicoli si riducono in dimensione e smettono di produrre spermatozoi.<ref>{{cita pubblicazione | autore=Brian M. Barnes, Maria Kretzmann, Paul Licht e Irving Zucker | data=1 dicembre 1986 | titolo=The Influence of Hibernation on Testis Growth and Spermatogenesis in the Golden-Mantled Ground Squirrel, Spermophilus Lateralis1 | rivista=Biology of Reproduction | volume=35 | numero=5 | pp=1289-1297 | doi=10.1095/biolreprod35.5.1289 | pmid=3828438 | issn=0006-3363}}</ref><ref>{{cita libro | autore=B. J. Verts e Leslie N. Carraway | url=https://www.worldcat.org/oclc/47011896 | titolo=Land mammals of Oregon | anno=1998 | editore=University of California Press | isbn=978-0-520-92031-6 | città=Berkeley | oclc=47011896}}</ref> Seguono poi le femmine adulte, i giovani di un anno (''yearlings''), e infine i giovani nati nell'anno precedente (''juveniles''). Gli animali che vivono ad altitudini e latitudini maggiori emergono più tardi.<ref name=r10/> Alle quote più basse emergono dal letargo e iniziano la stagione riproduttiva più precocemente.<ref name=r12/>
Essi allevano una sola cucciolata all'anno. I piccoli nascono nudi, ciechi e privi di denti. Dopo 5-6 giorni, il loro peso raddoppia. Intorno al dodicesimo giorno sono ricoperti da pelo scuro e setoso. Verso il diciassettesimo giorno, i loro occhi iniziano ad aprirsi. Possono emergere alla luce solare all'esterno della tana intorno al 21°-24° giorno. Dopo quattro settimane sono completamente in grado di lasciare il nido.<ref name=r12/>
The giraffe was one of the many species first described by [[Carl Linnaeus]] in 1758. He gave it the binomial name ''[[Cervus]] camelopardalis''. [[Morten Thrane Brünnich]] classified the genus ''Giraffa'' in 1772.<ref name="Dagg1971"/> In the early 19th century, [[Jean-Baptiste Lamarck]] believed the giraffe's long neck was an "acquired characteristic", developed as generations of ancestral giraffes strove to reach the leaves of tall trees.<ref name="Prothero 2003"/> This theory was eventually rejected, and scientists now believe the giraffe's neck arose through Darwinian [[natural selection]]—that ancestral giraffes with long necks thereby had a competitive advantage that better enabled them to reproduce and pass on their genes.<ref name="Prothero 2003"/>
Prima del loro primo letargo, i giovani citelli della Columbia hanno solo poche settimane a disposizione per svezzarsi dal latte materno.<ref>{{cita pubblicazione | autore=P. J. Young | data=luglio 1990 | titolo=Hibernating patterns of free-ranging Columbian ground squirrels | url=http://link.springer.com/10.1007/BF00317201 | rivista=Oecologia | volume=83 | numero=4 | pp=504-511 | doi=10.1007/BF00317201 | pmid=28313184 | bibcode=1990Oecol..83..504Y | issn=0029-8549}}</ref> Per questo motivo, i 27 giorni di allattamento rappresentano la loro principale occasione per accumulare le riserve energetiche necessarie per sopravvivere al letargo.<ref>{{cita pubblicazione | autore=J. O. Murie | data=26 maggio 1992 | titolo=Predation by Badgers on Columbian Ground Squirrels | url=https://academic.oup.com/jmammal/article-lookup/doi/10.2307/1382073 | rivista=Journal of Mammalogy | volume=73 | numero=2 | pp=385-394 | doi=10.2307/1382073 | jstor=1382073 | issn=1545-1542}}</ref> La composizione della maggior parte delle sostanze nutritive nel latte materno varia durante l'allattamento; il cambiamento più significativo riguarda il calcio, la cui concentrazione aumenta tipicamente del 134% dal periodo iniziale fino al suo picco (circa 17 giorni [[Puerperio|dopo il parto]]).<ref>{{cita pubblicazione | autore=Amy L. Skibiel e Wendy R. Hood | data=febbraio 2013 | titolo=Milk composition in a hibernating rodent, the Columbian ground squirrel ( Urocitellus columbianus ) | rivista=Journal of Mammalogy | volume=94 | numero=1 | pp=146-154 | doi=10.1644/1-MAMM-A-078.1 | issn=0022-2372}}</ref>
===Subspecies===
Up to nine subspecies of giraffe are recognised (with population estimates {{As of|2010|lc=y}}):
Il mammalogo [[Vernon Orlando Bailey]] esaminò una tana di citello della Columbia situata a un'altitudine di circa 2.100 metri vicino al Piegan Pass nel [[Parco nazionale dei ghiacciai (Stati Uniti d'America)|Glacier National Park]]. Alla fine di luglio, una femmina adulta fu osservata mentre portava quotidianamente terra fresca all'ingresso della tana. Dopo la rimozione dell'animale, la tana fu scavata per esaminarne la struttura interna. Il cumulo di terra all'ingresso ammontava approssimativamente a 0,030 m³. Il terreno accumulato era di date differenti, poiché gli strati inferiori risultavano compattati da stagioni precedenti. La tana aveva questo ingresso principale e due ingressi alternativi nascosti alla vista esterna, probabilmente utilizzati come vie di fuga in caso di predatori. I tunnel principali avevano un diametro di circa 89 mm. Lungo la tana erano presenti diverse camere, probabilmente destinate allo stoccaggio temporaneo della terra scavata o come rifugio in caso di pericolo. A circa 2,4 metri dall'ingresso, era stato costruito un nido realizzato con foglie della «''glacier grass''» (''[[Luzula parviflora]]''), un'erba abbondante nella zona. Nel nido erano presenti erbe di età differenti, suggerendo che fosse stato utilizzato durante stagioni precedenti. In una camera adiacente, più in profondità, vi era un vecchio nido abbandonato, parzialmente riempito di escrementi, che apparentemente veniva usato dal citello come latrina.<ref name=r18>{{cita|Bailey e Bailey, 1918|pp. 47-48}}.</ref>
{| class="wikitable" border="1"
[[File:Urocitellus columbianus.jpg|thumb|Standing at attention]]
|+ Subspecies of Giraffe
La presenza di due tipi di ingresso della tana è stata notata anche da altri osservatori: un tipo di apertura era piccolo e dello stesso diametro del tunnel, l'altro più grande e a forma di imbuto.<ref name=r19>{{cita|Elliott e Flinders, 1991|p. 3}}</ref> La quantità di terra scavata annualmente è stimata tra i 4 e i 12 kg, con una costruzione annuale di tunnel che varia dai 4 ai 7 metri. La costruzione di una nuova tana comporta lo scavo di 25-50 kg di terra.<ref name=r19/>
! Subspecies !! Description !! Image
|-
|'''[[Nubian giraffe]]''', (''G. c. camelopardalis'')<ref name= "MacDonald">{{Cite book|author=Pellow, R. A.|contribution=Giraffe and Okapi|year=2001|title=The Encyclopedia of Mammals|edition= 2nd|editor=MacDonald, D|publisher=Oxford University Press|pages=520–27|isbn=0-7607-1969-1}}</ref> || The [[nominate subspecies]], is found in eastern [[South Sudan]] and south-western [[Ethiopia]].<ref name=wildstatus/> It has sharply defined chestnut-coloured spots surrounded by mostly white lines, while undersides lack spotting. The median lump is particularly developed in the male.<ref name=Seymour>Seymour, R. (2002) The taxonomic status of the giraffe, ''Giraffa camelopardalis'' (L. 1758), PH.D Thesis</ref>{{rp|51}} Fewer than 250 are thought to remain in the wild, although this number is uncertain.<ref name=wildstatus>{{Cite web|url= http://www.giraffeconservation.org/giraffe_facts.php?pgid=40 |title= Giraffe – The Facts: Current giraffe status? |publisher=Giraffe Conservation Foundation |accessdate= 21 December 2010}}</ref> It is rare in captivity, although a group is kept at [[Al Ain Zoo]] in the [[United Arab Emirates]].<ref name='"Al Ain exhibits"'>{{cite web|title=Exhibits|url=http://www.awpr.ae/en/Visit/Pages/AfricanMixedExhibit.aspx|publisher=Al Ain Zoo|date=25 February 2003|accessdate= 21 November 2011}}</ref> In 2003, this group numbered 14.<ref>{{Cite web|url=http://www.uaeinteract.com/docs/Nubian_giraffe_born_in_Al_Ain_zoo/6971.htm|title=Nubian giraffe born in Al Ain zoo|publisher=UAE Interact|accessdate=21 December 2010}}</ref>
Le attività più comuni dei citelli della Columbia quando sono in superficie includono stare in posizione vigile eretta, nutrirsi e prendersi cura del proprio pelo (''grooming'').<ref name=r10/> Passano più tempo in posizione vigile rispetto ad altre attività. I comportamenti aggressivi sono più frequentemente osservati nei maschi adulti, soprattutto all'inizio della stagione.<ref name=r10/> I loro schemi di attività dipendono dal clima e dalla luminosità ambientale, evitando giorni nuvolose, venti freddi e cattivo tempo. Emergono dalle tane circa un'ora prima dell'alba e tornano al tramonto. Sono attivi durante le ore più calde della giornata, ma più frequentemente si osservano intorno a metà mattina.<ref name=r12/>
||[[File:Al Ain Zoo Giraffe.JPG|150px]]
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|'''[[Reticulated giraffe]]''' (''G. c. reticulata''),<ref name= "MacDonald"/> also known as '''Somali giraffe''' || Is native to north-eastern [[Kenya]], southern Ethiopia, and [[Somalia]].<ref name=wildstatus/> Its distinctive coat pattern consists of sharp-edged, reddish brown polygonal patches divided by a network of thin white lines. Spots may or may not extend bellow the hocks and a median lump is present in males.<ref name=Seymour/>{{rp|53}} An estimated maximum of 5,000 remain in the wild,<ref name=wildstatus/> and based on [[International Species Information System]] records, more than 450 are kept in zoos.<ref name=ISIS>{{cite web|url=https://app.isis.org/abstracts/Abs77545.asp|title= Giraffa |publisher=[[International Species Information System|ISIS]]|year=2010|accessdate= 4 November 2010}}</ref>
Quando i citelli della Columbia si incontrano tra loro, spesso si toccano reciprocamente la bocca e il naso, compiendo un atto simile a un bacio. Questi saluti durano da 1 a 5 secondi e possono precedere altre interazioni sociali, inclusa l'attività sessuale.<ref name=r10/>
||[[File:Two Giraffes.PNG|150px]]
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|'''[[Angolan giraffe]]''' (''G. c. angolensis''), also known as '''Namibian giraffe''' || Is found in northern [[Namibia]], south-western [[Zambia]], [[Botswana]], and western [[Zimbabwe]]. A 2009 genetic study on this subspecies suggests the northern [[Namib Desert]] and [[Etosha National Park]] populations form a separate subspecies.<ref>{{cite journal|doi= 10.1111/j.1365-2028.2009.01078.x|author= Brenneman, R. A.; Louis, E. E. Jr; Fennessy, J. |year=2009|title=Genetic structure of two populations of the Namibian giraffe, ''Giraffa camelopardalis angolensis''|journal=African Journal of Ecology|volume=47|issue=4|pages=720–28}}</ref> This subspecies has large brown blotches with edges that are either somewhat notched or have angular extensions. The spotting pattern extends throughout the legs but not the upper part of the face. The neck and rump patches tend to be fairly small. The subspecies also has a white ear patch.<ref name=Seymour/>{{rp|51}} A maximum of 20,000 animals are estimated to remain in the wild;<ref name=wildstatus/> and about 20 are kept in zoos.<ref name=ISIS/>
[[Clinton Hart Merriam|C. Hart Merriam]], scrivendo nel 1891, riportò osservazioni locali sul comportamento di questi citelli in Idaho. Se disturbati fuori dalla tana, si ergevano in posizione vigile, osservando fino a quando qualcuno non si avvicinava a pochi metri, poi correvano rapidamente verso la tana emettendo fischi e squittii. Gli abitanti locali li chiamavano ''Seven sleepers'' («sette dormienti») perché trascorrevano circa sette mesi all'anno sottoterra. Vennero descritti come ben forniti di grasso al momento di entrare in letargo, ma molto magri e deboli quando riemergevano la primavera successiva. I cumuli di terra scavati dai citelli avevano un'altezza compresa tra 7 a 25 cm di altezza. Le tane scendevano verticalmente per 46-61 cm.<ref name=r20>{{cita|Merriam, 1891|p. 40}}.</ref>
||[[File:Giraffa camelopardalis -Zambia-8.jpg|150px]]
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|'''[[Kordofan giraffe]]''' (''G. c. antiquorum'') || Has a distribution which includes southern [[Chad]], the [[Central African Republic]], northern [[Cameroon]], and north-eastern [[Democratic Republic of the Congo|DR Congo]]. Populations in Cameroon were formerly included in ''G. c. peralta'', but this was incorrect.<ref name=WestAfricaGiraffe>{{Cite journal|author=Hassanin, A.; Ropiquet, A.; Gourmand, B-L.; Chardonnet, B.; Rigoulet, J.|year=2007|title= Mitochondrial DNA variability in Giraffa camelopardalis: consequences for taxonomy, phylogeography and conservation of giraffes in West and central Africa|journal=Comptes Rendus Biologies|volume=330|issue=3|pages= 173–83|pmid= 17434121|doi=10.1016/j.crvi.2007.02.008}}</ref> Compared to the Nubian giraffe, this subspecies has smaller and more irregular spotting patterns. Its spots may be found below the hocks and the insides of the legs. A median lump is present in males.<ref name=Seymour/>{{rp|51–52}} A maximum of 3,000 are believed to remain in the wild.<ref name=wildstatus/> Considerable confusion has existed over the status of this subspecies and ''G. c. peralta'' in zoos. In 2007, all alleged ''G. c. peralta'' in [[List of zoos#Europe|European zoos]] were shown to be, in fact, ''G. c. antiquorum''.<ref name=WestAfricaGiraffe/> With this correction, about 65 are kept in zoos.<ref name=ISIS/> The formely recognised subspecies ''G. c. congoesis'' is now considered part of Kordofan subspecies.
== Ecologia ==
||[[File:Giraffa camelopardalis antiquorum (Vincennes Zoo) 2.jpg|150px]]
[[File:Squirrel Posing at Logan Pass.jpg|thumb|left|Squirrel posing at Logan Pass]]
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I citelli della Columbia vivono in colonie distribuite in modo discontinuo all'interno del loro areale. Sono presenti in habitat alpini e subalpini, ai margini di prati o su cumuli rialzati dove si verificano inondazioni stagionali. Non si trovano frequentemente in ambienti rocciosi, praterie alpine sassose (''fellfield''), lande di erica (''heather'') o aree erbose alpine (''herbfield'') come invece avviene in prati e praterie. Possono anche occupare habitat disturbati, incluse le aree disboscate. In zone in cui [[Simpatria|coabitano]] con il citello di Belding (''[[Urocitellus beldingi]]''), occupano le aree con altitudine maggiore e clima più umido. Il citello di Belding preferisce invece regioni più secche e caratterizzate da vegetazione arbustiva di artemisia.<ref name=r19/> In Oregon, il citello della Columbia si trova principalmente nelle Blue Mountains, insieme ad altri mammiferi caratteristici tra cui: il toporagno montano (''[[Sorex monticolus]]''), il citello di Belding (''[[Urocitellus beldingi]]''), lo scoiattolo rosso (''[[Tamiasciurus hudsonicus]]''), il gopher del nord (''Thomomys talpoides''), il campagnolo rossastro del nord (''Clethrionomys gapperi'') e lo zapo occidentale (''[[Zapus princeps]]'').<ref name=r21>{{cita|Verts e Carraway, 1998|p. 33}}.</ref>
|'''[[Masai giraffe]]''' (''G. c. tippelskirchi''), also known as '''[[Kilimanjaro]] giraffe''' || Can be found in central and southern Kenya and in [[Tanzania]].<ref name=wildstatus/> It has distinctive, irregular, jagged, star-like blotches which extend to the hooves. A median lump is usually present in males.<ref name=Seymour/>{{rp|54}}<ref name=estes/> A maximum of 40,000 are thought to remain in the wild,<ref name=wildstatus/> and about 100 are kept in zoos.<ref name=ISIS/>
Non è nota alcuna descrizione di predazione da parte dei citelli della Columbia verso altri vertebrati. Tuttavia, è stato osservato il cannibalismo. In alcuni casi, le femmine adulte possono anche uccidere i piccoli. È stato ipotizzato che specie simpatriche, come il gopher del nord, il peromisco cervo (''[[Peromyscus maniculatus]]'') e l'arvicola della Pennsylvania (''[[Microtus pennsylvanicus]]''), possano sfruttare o depredare tane già fornite di provviste. Nel 1985 furono riportate osservazioni relative a possibili uccisioni di arvicole della Pennsylvania da parte dei citelli della Columbia. Tali uccisioni non sembravano motivate dalla predazione, ma piuttosto dalla difesa del territorio e delle risorse.<ref name=r22>{{cita|Harris, 1985}}.</ref>
||[[File:GiraffaCamelopardalisTippelskirchi-Masaai-Mara.JPG|150px]]
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|'''[[Rothschild's giraffe]]''' (''G. c. rothschildi'', after [[Walter Rothschild, 2nd Baron Rothschild|Walter Rothschild]]),<ref name= "MacDonald"/> also known as '''[[Lake Baringo|Baringo]] giraffe''' or '''[[Uganda]]n giraffe''' ||Its range includes parts of Uganda and Kenya.<ref name=iucn/> Its presence in South Sudan is uncertain.<ref name=IUCNrothschildi>{{IUCN2012.2|assessors=Fennessy, J. & Brenneman, R.|year=2010|id=174469|title=Giraffa camelopardalis ssp. rothschildi|downloaded=2013-01-26}}</ref> This giraffe has large dark patches that usually have complete margins, but may also have sharp edges. The dark spots may also have paler radiating lines or streaks within them. Spotting does not often reach below the hocks and almost never to the hooves. This subspecies may also develop five "horns".<ref name=Seymour/>{{rp|53}} Fewer than 700 are believed to remain in the wild,<ref name=wildstatus/> and more than 450 are kept in zoos.<ref name=ISIS/>
Le densità delle popolazioni risulta più alta nei «terreni agricoli di fondo valle» rispetto ai «campi di grano». Nell'Idaho subalpino è stata rilevata una densità di 35 individui per ettaro. In Alberta, la densità di giovani è stata stimata tra 5 e 20 per ettaro, mentre per gli individui più anziani la stima varia da 12 a 16 per ettaro.<ref name=r19/>
||[[File:Giraffa camelopardalis rothschildi 1.jpg|150px]]
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|'''[[South African giraffe]]''' (''G. c. giraffa'') || Is found in northern [[South Africa]], southern Botswana, southern Zimbabwe, and south-western [[Mozambique]].<ref name=wildstatus/> It has dark, somewhat rounded patches "with some fine projections" on a tawny background colour. The spots extend down the legs and get smaller. The median lump of males is less developed.<ref name=Seymour/>{{rp|52}} A maximum of 12,000 are estimated to remain in the wild,<ref name=wildstatus/> and around 45 are kept in zoos.<ref name=ISIS/>
I citelli della Columbia sono descritti come «tra i citelli più vegetariani in assoluto». Nella prima parte della stagione, si nutrono prevalentemente di vegetazione fresca e succulenta. Quando la vegetazione diventa più dura, si orientano maggiormente verso semi e granaglie. Alla fine della stagione, appaiono visibilmente ingrassati. L'esame del contenuto gastrico di un gruppo di 43 citelli ha rivelato materiale vegetale in tutti i casi. Nell'86% degli stomaci analizzati fu rinvenuta esclusivamente vegetazione, mentre il 2% conteneva tracce di altri mammiferi e il 14% resti di insetti.<ref name=r12/>
||[[File:Giraffe standing.jpg|150px]]
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|'''[[Rhodesian giraffe]]''' (''G. c. thornicrofti'', after [[Harry Scott Thornicroft]]),<ref name= "MacDonald"/> also known as '''Thornicroft giraffe''' ||Is restricted to the [[Luangwa River|Luangwa Valley]] in eastern Zambia.<ref name=wildstatus/> The patches are notched and somewhat star-shaped, and may or may not extend across the legs. The median lump of males is underdeveloped.<ref name=Seymour/>{{rp|54}} No more than 1,500 remain in the wild,<ref name=wildstatus/> with none kept in zoos.<ref name=ISIS/>
I citelli della Columbia possono essere parassitati dalla zecca delle Montagne Rocciose (''[[Dermacentor andersoni]]''), vettore dei batteri che causano la [[febbre maculosa delle Montagne Rocciose]]. Altri parassiti esterni includono i pidocchi ''Enderleinellus suturalis'' e ''Neohaemotopinus laeviusculus''; le pulci ''Neopsylla inopina'', ''Opisocrostis tuberculatus'' e ''Oropsylla idahoensis''; gli acari ''Dermacarus heptneri'', ''Androlaelaps fahrenholz'', ''[[Macrocheles]] sp. e ''Pygmephorus erlangensis''. Tra i parassiti interni vi sono il protozoo ''Trypanosoma otospermophili'' e le specie del genere ''[[Eimeria]]'': ''Eimeria bilamellata'', ''Eimeria callospermophili'' e ''Eimeria lateralis''. È stata segnalata anche la presenza di ''[[Yersinia pestis]]'', causa della [[peste nera]]. Essi possono fungere da riserva naturale per virus come quelli dell'encefalite di Powassan o di Saint Louis, sulla base di alcune analisi sierologiche. I citelli della Columbia possono inoltre soffrire di dermatite provocata da ''Dermatophilus congolensis''.<ref name=r23>{{cita|Elliott e Flinders, 1991|p. 4}}.</ref>
||[[File:Giraffa camelopardalis thornicrofti.jpg|150px]]
[[File:Columbian Ground Squirrel Cranbrook.jpg|left|thumb|Columbian ground squirrel in [[North Central Rockies forests|North Central Rockies Forests]]]]
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Il trattamento delle femmine di citello della Columbia con polvere antipulci ha prodotto un miglioramento nelle condizioni fisiche degli animali trattati. Le femmine trattate hanno prodotto cucciolate più numerose e guadagnato peso dalla nascita allo svezzamento dei piccoli, mentre quelle non trattate hanno perso peso nello stesso periodo.<ref>{{cita pubblicazione | autore=P. Neuhaus | titolo=Parasite removal and its impact on litter size and body condition in Columbian ground squirrels (Spermophilus columbianus) | rivista=Proceedings of the Royal Society B: Biological Sciences | data=7 novembre 2003 | volume=270 | numero=Suppl_2 | pp=S213-S215 | doi=10.1098/rsbl.2003.0073 | pmid=14667386 | pmc=1809932}}</ref>
|The '''[[West African giraffe]]''' (''G. c. peralta''),<ref name= "MacDonald"/> also known as '''[[Niger]] giraffe''' or '''[[Nigeria]]n giraffe'''<ref name=IUCNperalta>{{IUCN2012.2|assessors=Fennessy, J.; Brown, D.|year=2008|id=136913|title=Giraffa camelopardalis ssp. peralta|downloaded=2013-01-26}}</ref> || Is [[Endemism|endemic]] to south-western Niger.<ref name=iucn/> This animal has a lighter pelage than other subspecies,<ref name=Kingdon1988/>{{rp|322}} with red lobe-shaped blotches that reach below the hocks. The ossicones are more erect than in other subspecies and males have well-developed median lumps.<ref name=Seymour/>{{rp|52–53}} It is the most endangered subspecies with fewer than 220 individuals remaining in the wild.<ref name=wildstatus/> Giraffes in Cameroon were formerly believed to belong to this subspecies, but are actually ''G. c. antiquorum''.<ref name=WestAfricaGiraffe/> This error resulted in some confusion over its status in zoos, but in 2007, it was established that all "''G. c. peralta''" kept in European zoos actually are ''G. c. antiquorum''.<ref name=WestAfricaGiraffe/>
Tra i predatori del citello della Columbia vi sono l'orso grizzly (''[[Ursus arctos horribilis]]''), il coyote (''[[Canis latrans]]''), la martora del Pacifico (''[[Martes caurina]]''), il lupo (''[[Canis lupus]]''), il tasso americano (''[[Taxidea taxus]]''), varie specie di [[Mustelidae|donnole]] (''[[Mustela]]'' e ''[[Neogale]]''), e il puma (''[[Puma concolor]]''). Tra gli uccelli predatori vi sono l'aquila reale (''[[Aquila chrysaetos]]''), la poiana della Giamaica (''[[Buteo jamaicensis]]'') e l'astore (''[[Accipiter gentilis]]'').<ref name=r23/>
||[[File:Giraffe koure niger 2006.jpg|150px]]
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[[File:Genetic subdivision in the giraffe based on mitochondrial DNA sequences.png|thumb|300px|right|"Approximate geographic ranges, fur patterns, and [[phylogenetics|phylogenetic]] relationships between some giraffe subspecies based on [[mitochondrial DNA]] sequences. Colored dots on the map represent sampling localities. The phylogenetic tree is a [[maximum-likelihood]] [[Phylogenetic tree#Special tree types|phylogram]] based on samples from 266 giraffes. Asterisks along branches correspond to [[Clade#Definitions|node]] values of more than 90% [[Resampling (statistics)|bootstrap]] support. Stars at branch tips identify [[paraphyletic]] [[haplotype]]s found in Maasai and Reticulated giraffes".<ref name=GeneticStructure>{{cite journal|title=Extensive population genetic structure in the giraffe|author=Brown, D. M.; Brenneman R. A.; Koepfli, K-P.; Pollinger, J. P.; Milá, B.; Georgiadis, N. J.; Louis Jr., E. E.; Grether, G. F.; Jacobs, D. K.; Wayne R. K.|journal= BMC Biology |year=2007|volume=5|issue=1|page=57|doi=10.1186/1741-7007-5-57|pmc=2254591|pmid=18154651}}</ref>]]
A 2007 study on the genetics of six subspecies—the West African, Rothschild's, reticulated, Masai, Angolan, and South African giraffe—suggests they may, in fact, be separate species. The study deduced from [[genetic drift]] in [[nuclear DNA|nuclear]] and [[mitochondrial DNA]] (mtDNA) that giraffes from these populations are [[Reproductive isolation|reproductively isolated]] and rarely interbreed, though no natural obstacles block their mutual access. This includes adjacent populations of Rothschild's, reticulated, and Masai giraffes. The Masai giraffe may also consist of a few species separated by the [[East African Rift|Rift Valley]].<ref name=GeneticStructure/>
== Tassonomia ==
Reticulated and Masai giraffes have the highest mtDNA diversity, which is consistent with giraffes originating in eastern Africa. Populations further north are more closely related to the former, while those to the south are more related to the latter. Giraffes appear to select mates of the same coat type, which are imprinted on them as calves.<ref name=GeneticStructure/> The implications of these findings for the conservation of giraffes were summarised by David Brown, lead author of the study, who told [[BBC News]]: "Lumping all giraffes into one species obscures the reality that some kinds of giraffe are on the brink. Some of these populations number only a few hundred individuals and need immediate protection."<ref>{{Cite news|publisher=BBC News|title=Not one but 'six giraffe species'|author= Lever, A-M.|date=21 December 2007|url=http://news.bbc.co.uk/1/hi/sci/tech/7156146.stm |accessdate=4 March 2009}}</ref>
[[File:Urocitellus columbianus 2 (Glacier NP, 2009).jpg|thumb|right|Columbian ground squirrel]]
In 1891, Merriam published an account of the mammals of Idaho, based on an expedition. He concluded that the Columbian ground squirrel is the same animal as the "Burrowing Squirrel" reported by [[Lewis and Clark]]. At the time, that animal had been thought to be the prairie dog. However, Merriam's assessment was that this was not the case and the animal described by Lewis and Clark was the same as an animal described by naturalist [[John Richardson (naturalist)|John Richardson]] in 1829.{{sfn|Merriam|1891|pp=40–41}} Richardson described it as a variant of the Arctic ground squirrel, obtained from the Rocky Mountains near the source of the Elk River.{{sfn|Richardson|1829|p=106}} Merriam knew of the presence of the squirrel, but his party was there late in the season and no squirrels were directly observed in the field.{{sfn|Merriam|1891|p=40}} However, Merriam reported that he was able to obtain "a fine series of specimens" from near Moscow, within about {{convert|40|m|km}} from the locale where Lewis and Clark's obtained their specimens. Other were obtained from a site even closer. Based on his observations and comparison with the notes of Lewis and Clark, Merriam assessed that the Columbian ground squirrel was not a variant of the Arctic ground squirrel, but a separate species, which he named as ''Spermophilus columbianus'', rejecting the genus designation ''Arctomys'' and reapplying the species designation originally applied by [[George Ord|Ord]] in 1815.{{sfn|Merriam|1891|pp=40–41}}
Two subspecies are described. The first, ''Spermophilus columbianus columbianus'' is the type described by Ord in 1815. The specimen type was taken "between the forks of the Clearwater and Kooskooskie rivers", in [[Idaho]].{{sfn|Thorington|Hoffman|2005|p=806}} ''Spermophilus columbianus albertae'', described in 1903 by [[Joel Asaph Allen]], is a synonym. Another synonymous designation, ''Anisonyx brachiura'', was applied by [[Constantine Samuel Rafinesque|Rafinesque]] in 1817. The third synonym, ''Spermophilus columbianus erythrogluteia'', was the animal designated by Richardson in 1829.{{sfn|Helgen|Cole|Helgen|Wilson|2009|p=297}}
The West African giraffe is more closely related to Rothchild's and reticulated giraffes than to the Kordofan giraffe. Its ancestor may have migrated from eastern to northern Africa and then to its current range with the development of the Sahara Desert. At its largest, [[Lake Chad]] may have acted as a barrier between West African and Kordofan giraffes during the [[Holocene]].<ref name=WestAfricaGiraffe/>
The second subspecies, ''Spermophilus columbianus ruficaudus'' was described in 1928 by [[Arthur H. Howell]].{{sfn|Thorington|Hoffman|2005|p=806}} The type was taken near [[Wallowa Lake]] in northeastern Oregon.{{sfn|Elliott|Flinders|1991|p=1}}
==Appearance and anatomy==
{{commons category|Giraffa camelopardalis anatomy}}
[[File:Giraffe08 - melbourne zoo.jpg|thumb|thumb|Closeup of the head of a giraffe at the [[Melbourne Zoo]]]]
[[File:Giraffe skeleton.jpg|thumb|Giraffe skeleton on display at the [[Museum of Osteology]], [[Oklahoma City, Oklahoma]]]]
Fully grown giraffes stand {{convert|5|–|6|m|abbr=on}} tall, with males taller than females.<ref name="Dagg1971">{{Cite journal|author=Dagg, A. I.|year=1971|title=Giraffa camelopardalis|journal= Mammalian Species|volume=5|pages=1–8|url= http://www.science.smith.edu/msi/pdf/i0076-3519-005-01-0001.pdf|doi=10.2307/3503830|issue=5|jstor=3503830}}</ref> The average weight is {{convert|1192|kg|lb|abbr=on}} for an adult male and {{convert|828|kg|lb|abbr=on}} for an adult female<ref name="Skinner1990">{{Cite book|author=Skinner, J. D.; Smithers, R. H. M.|year=1990|title=The mammals of the southern African subregion|pages=616–20|publisher=University of Pretoria|isbn=0-521-84418-5}}</ref> with maximum weights of {{convert|1930|kg|lb|abbr=on}} and {{convert|1180|kg|lb|abbr=on}} having been recorded for males and females, respectively.<ref name="OwenSmith1988">Owen-Smith, R.N. 1988. Megaherbivores: The Influence of Very Large Body Size on Ecology. Cambridge: Cambridge University Press.</ref> Despite its long neck and legs, the giraffe's body is relatively short.<ref name=anatomy/>{{rp|66}} Located at both sides of the head, the giraffe's large, bulging eyes give it good all-round vision from its great height.<ref name=Williams/>{{rp|25}} Giraffes see in colour<ref name=Williams/>{{rp|26}} and their senses of hearing and [[olfaction|smell]] are also sharp.<ref name="Prothero 2003"/> The animal can close its muscular nostrils to protect against sandstorms and ants.<ref name=Williams/>{{rp|27}} The giraffe's [[prehensile]] tongue is about {{convert|50|cm|in|abbr=on}} long. It is purplish-black in colour, perhaps to protect against sunburn, and is useful for grasping foliage, as well as for grooming and cleaning the animal's nose.<ref name=Williams/>{{rp|27}} The upper lip of the giraffe is also prehensile and useful when foraging. The lips, tongue, and inside of the mouth are covered in [[Taste bud|papillae]] to protect against thorns.<ref name="Dagg1971"/>
[[File:Giraffa camelopardalis reticulata-atTobuZoo-2012.ogv|thumb|(video) A pair of giraffes at [[Tobu Zoo]], in [[Saitama prefecture|Saitama]], Japan]]
They have also been referred to as the burrowing squirrel.{{sfn|Bailey|1936|p=147}}
The coat has dark blotches or patches (which can be orange, [[Chestnut (color)|chestnut]], brown, or nearly black in colour<ref name="Prothero 2003"/>) separated by light hair (usually white or [[Cream (colour)|cream]] in colour<ref name="Prothero 2003"/>). Male giraffes become darker as they age.<ref name=estes>{{Cite book|title=The Behavior Guide to African Mammals: including Hoofed Mammals, Carnivores, Primates|author=Estes, R.|publisher=University of California Press|pages=202–07|year=1992|isbn=0-520-08085-8}}</ref> The coat pattern serves as [[camouflage]], allowing it to blend in the light and shade patterns of savanna woodlands.<ref name= "MacDonald"/> While adult giraffes standing among trees and bushes are hard to see at even a few metres' distance, when moving about to gain the best view of an approaching predator, they rely on their size and ability to defend themselves rather than on camouflage, which appears to be more important for calves.<ref name="Mitchell20003"/> The skin underneath the dark areas may serve as windows for [[thermoregulation]], being sites for complex blood vessel systems and large sweat glands.<ref name=Mitchell2004>{{Cite journal|author=Mitchell, G.; Skinner, J.D.|year=2004|title=Giraffe thermoregulation: a review|journal=Transactions of the Royal Society of South Africa: Proceedings of a Colloquium on Adaptations in Desert Fauna and Flora|volume=59|issue=2|pages=49–57|issn=0035-919X|url=http://www.sabinet.co.za/abstracts/royalsa/royalsa_v59_n2_a13.html|doi=10.1080/00359190409519170}}</ref> Each individual giraffe has a unique coat pattern.<ref name=estes/> The skin of a giraffe is mostly gray.<ref name="Skinner1990"/> It is also thick and allows it to run through thorn bush without being punctured.<ref name=Williams/>{{rp|34}} The fur may serve as a chemical defence, as its parasite repellents give the animal a characteristic scent. At least 11 main [[aromaticity|aromatic]] chemicals are in the fur, although [[indole]] and [[3-methylindole]] are responsible for most of the smell. Because the males have a stronger odor than the females, the odor may also have sexual function.<ref>{{Cite journal|author=Wood, W. F.; Weldon, P. J.|year=2002|title=The scent of the reticulated giraffe (''Giraffa camelopardalis reticulata'')|journal=Biochemical Systematics and Ecology|volume=30|issue=10|pages=913–17|doi=10.1016/S0305-1978(02)00037-6}}</ref> Along the animal's neck is a mane made of short, erect hairs.<ref name="Dagg1971"/> The one-metre (3.3-ft) tail ends in a long, dark tuft of hair and is used as a defense against insects.<ref name=Williams/>{{rp|36}}
Below is a [[cladogram]] of ground squirrels (tribe [[Marmotini]]) derived from maximum parsimony analysis.{{sfn|Helgen|Cole|Helgen|Wilson|2009|p=274}}
===Skull and ossicones===
Both sexes have prominent horn-like structures called [[ossicone]]s, which are formed from ossified [[cartilage]], covered in skin and fused to the skull at the [[parietal bone]]s.<ref name=estes/> Being [[vascular]]ized, the ossicones may have a role in thermoregulation,<ref name=Mitchell2004/> and are also used in combat between males.<ref name="sim2010"/> Appearance is a reliable guide to the sex or age of a giraffe: the ossicones of females and young are thin and display tufts of hair on top, whereas those of adult males end in knobs and tend to be bald on top.<ref name=estes/> Also, a median lump, which is more prominent in males, emerges at the front of the [[skull]].<ref name="Dagg1971"/> Males develop [[calcium]] deposits that form bumps on their skulls as they age.<ref name="Prothero 2003"/> A giraffe's skull is lightened by multiple [[Sinus (anatomy)|sinuses]].<ref name=anatomy/>{{rp|70}} However, as males age, their skulls become heavier and more club-like, helping them become more dominant in combat.<ref name=estes/> The upper jaw has a grooved [[palate]] and lacks front teeth.<ref name=Williams/>{{rp|26}} The giraffe's [[Molar (tooth)|molar]]s have a rough surface.<ref name=Williams/>{{rp|27}}
{{clade| style=font-size:85%; line-height:85%
===Legs, locomotion and posture===
|1={{clade
The front and back legs of a giraffe are about the same length. The [[Radius (bone)|radius]] and [[ulna]] of the front legs are articulated by the [[carpus]], which, while structurally equivalent to the human wrist, functions as a knee.<ref>{{cite book|author=MacClintock, D.; Mochi, U.|year=1973|title=A natural history of giraffes|publisher=Scribner|page=30|isbn=0-684-13239-7}}</ref> It appears that a [[suspensory ligament]] allows the lanky legs to support the animal's great weight.<ref>{{cite web|author=Wood, C.|date=7 March 2014|title=Groovy giraffes…distinct bone structures keep these animals upright|publisher=Society for Experimental Biology|url=http://www.eurekalert.org/pub_releases/2014-07/sfeb-ggd070314.php|accessdate=7 May 2014}}</ref> The foot of the giraffe reaches a diametre of {{convert|30|cm|in|abbr=on}}, and the [[hoof]] is {{convert|15|cm|in|abbr=on}} high in males and {{convert|10|cm|in|abbr=on}} in females.<ref name=Williams/>{{rp|36}} The rear of each hoof is low and the [[fetlock]] is close to the ground, allowing the foot to provide additional support to the animal's weight.<ref name="Dagg1971"/> Giraffes lack [[dewclaw]]s and interdigital glands. The giraffe's pelvis, though relatively short, has an [[Ilium (bone)|ilium]] that is outspread at the upper ends.<ref name="Dagg1971"/>
|1={{clade
|label1=''[[Notocitellus]]''
|1={{clade
|1=''N. adocetus''
|2=''N. annulatus'' }}
|label2=''[[Ammospermophilus]]''
|2={{clade
|1=''A. harrisii''
|2={{clade
|1=''A. leucurus''
|2={{clade
|1=''A. harrisii''
|2=''A. interpres'' }} }} }} }}
|2={{clade
|1={{clade
|label1=''[[Otospermophilus]]''
|1={{clade
|1={{clade
|1=''O. atricapillus''
|2=''O. beecheyi'' }}
|2=''O. variegatus'' }}
|label2=''[[Callospermophilus]]''
|2={{clade
|1=''C. saturatus''
|2={{clade
|1=''C. lateralis''
|2=''C. madrensis'' }} }} }}
|2={{clade
|label1=''[[Marmota]]''
|1={{clade
|1=''M. monax''
|2=''M. marmota''
|3={{clade
|1=''M. flaviventris''
|2={{clade
|1=''M. caligata''
|2={{clade
|1=''M. olympus''
|2=''M. vancouveriensis'' }} }} }}
|4={{clade
|1={{clade
|1=''M. broweri''
|2={{clade
|1=''M. menzbieri''
|2=''M. caudata'' }} }}
|2={{clade
|1={{clade
|1=''M. baibacina''
|2=''M. bobak'' }}
|2={{clade
|1=''M. camtschatica''
|2={{clade
|1=''M. himalayana''
|2=''M. sibirica'' }} }} }} }} }} }} }} }}
|2={{clade
|label1=''[[Spermophilus]]''
|1={{clade
|1={{clade
|1=''S. musicus''
|2={{clade
|1=''S. pygmaeus''
|2={{clade
|1=''S. major''
|2=''S. pygmaeus'' }} }} }}
|2={{clade
|1={{clade
|1={{clade
|1=''S. dauricus''
|2=''S. xanthopyrmnus'' }}
|2=''S. suslicus'' }}
|2={{clade
|1=''S. citellus''
|2={{clade
|1=''S. relictus''
|2={{clade
|1=''S. erythrogenys''
|2={{clade
|1=''S. citellus''
|2={{clade
|1=''S. pallidicauda''
|2={{clade
|1=''S. fulvus''
|2={{clade
|1=''S. erythrogenys''
|2=''S. major'' }} }} }} }} }} }} }} }} }}
|2={{clade
|1={{clade
|label1=''[[Ictidomys]]''
|1={{clade
|1=''I. mexicanus''
|2={{clade
|1=''I. parvidens''
|2=''I. tridecemlineatus'' }} }}
|2={{clade
|label1=''[[Poliocitellus]]''
|1=''P. franklinii''
|2={{clade
|label1=''[[Cynomys]]''
|1={{clade
|1={{clade
|1=''C. ludovicianus''
|2=''C. mexicanus'' }}
|2={{clade
|1=''C. parvidens''
|2={{clade
|1=''C. gunnisoni''
|2=''C. leucurus'' }} }} }}
|label2=''[[Xerospermophilus]]''
|2={{clade
|1={{clade
|1=''X. mohavensis''
|2=''X. tereticaudus'' }}
|2={{clade
|1=''X. spilosoma''
|2={{clade
|1=''X. perotensis''
|2=''X. spilosoma'' }} }} }} }} }} }}
|label2=''[[Urocitellus]]''
|2={{clade
|1=''U. townsendii''
|2={{clade
|1=''U. washingtonii''
|2={{clade
|1={{clade
|1=''U. brunnenus''
|2={{clade
|1=''U. townsendii''
|2={{clade
|1=''U. mollis''
|2=''U. townsendii'' }} }} }}
|2={{clade
|1={{clade
|1=''U. armatus''
|2=''U. beldingi'' }}
|2={{clade
|1=''U. columbianus''
|2={{clade
|1=''U. undulatus''
|2={{clade
|1=''U. parryii''
|2={{clade
|1=''U. elegans''
|2=''U. richardsonii'' }}
|3=''U. parryii'' }} }} }} }} }} }} }} }} }} }}
==Human interactions==
A giraffe has only two [[gait]]s: walking and galloping. Walking is done by moving the legs on one side of the body at the same time, then doing the same on the other side.<ref name=estes/> When galloping, the hind legs move around the front legs before the latter move forward,<ref name="Prothero 2003"/> and the tail will curl up.<ref name=estes/> The animal relies on the forward and backward motions of its head and neck to maintain balance and the counter momentum while galloping.<ref name=Kingdon1988/>{{rp|327–29}} The giraffe can reach a sprint speed of up to {{convert|60|km/h|abbr=on}},<ref>{{Cite journal |last1= Garland |first1=T |last2=Janis |first2=C. M. | year = 1993 | title = Does metatarsal/femur ratio predict maximal running speed in cursorial mammals? | url = http://www.biology.ucr.edu/people/faculty/Garland/GarlandJanis1993.pdf | journal = Journal of Zoology | volume = 229 | issue = 1 | pages = 133–51 | doi = 10.1111/j.1469-7998.1993.tb02626.x }}</ref> and can sustain {{convert|50|km/h|abbr=on}} for several kilometres.<ref>{{Cite book|author=Rafferty, John. P|year=2011|title=Grazers (Britannica Guide to Predators and Prey)|publisher=Britannica Educational Publishing|page=194|isbn=1-61530-336-7}}</ref>
[[File:George Ord, in Rhoads reprint.jpg|thumb|left|upright|Ornithologist [[George Ord]] published the first scientific description of the Columbia ground squirrel]]
With the advent of intensive agricultural practices in their range, Columbian ground squirrels came to be seen as pests, negatively impacting harvests of wheat and other crops. In 1910, the Washington Agricultural Experiment Station began a comprehensive study in a ___location known as ''the Citellary'' (named after the contemporary genus name of the animal ''Citellus''). ''The Citellary'' was composed of yards that enclosed natural squirrel dens and was 50 by 90 feet, surrounded by a fence. Associated cabins were used for the study of brooding and hibernating animals. This provided conditions to closely observe them in a near natural setting.{{sfn|Shaw|1918}}
===Conservation status===
A giraffe rests by lying with its body on top of its folded legs.<ref name=Kingdon1988>{{Cite book|author=Kingdon, J. |year=1988|title=East African Mammals: An Atlas of Evolution in Africa, Volume 3, Part B: Large Mammals|pages=313–37|publisher=University Of Chicago Press |isbn=0-226-43722-1}}</ref>{{rp|329}} To lie down, the animal kneels on its front legs and then lowers the rest of its body. To get back up, it first gets on its knees and spreads its hind legs to raise its hindquarters. It then straightens its front legs. With each step, the animal swings its head.<ref name=Williams/>{{rp|31}} In captivity, the giraffe sleeps intermittently around 4.6 hours per day, mostly at night.<ref name=sleep/> It usually sleeps lying down, however, standing sleeps have been recorded, particularly in older individuals. Intermittent short "deep sleep" phases while lying are characterised by the giraffe bending its neck backwards and resting its head on the hip or thigh, a position believed to indicate [[paradoxical sleep]].<ref name=sleep>{{cite journal|last=Tobler|first=I.|last2=Schwierin|first2=B.|title=Behavioural sleep in the giraffe (''Giraffa camelopardalis'') in a zoological garden|year=1996|journal=Journal of Sleep Research|volume=5|issue=1|pages=21–32|doi=10.1046/j.1365-2869.1996.00010.x|pmid=8795798}}</ref> If the giraffe wants to bend down to drink, it either spreads its front legs or bends its knees.<ref name=estes/> Giraffes would probably not be competent swimmers as their long legs would be highly cumbersome in the water,<ref name = "swim">{{cite journal | doi = 10.1016/j.jtbi.2010.04.007 | author = Henderson, D. M.; Naish, D. | year = 2010 | title = Predicting the buoyancy, equilibrium and potential swimming ability of giraffes by computational analysis | url = | journal = Journal of Theoretical Biology | volume = 265 | issue = 2| pages = 151–59 | pmid = 20385144 }}</ref> although they could possibly float.<ref name="Naish">{{cite journal| last = Naish | first = D. | author-link = Darren Naish |date= January 2011 | title = Will it Float? | periodical = [[Scientific American]] | issn = 0036-8733 | volume = 304 | issue = 1 | page = 22| url = http://www.scientificamerican.com/article.cfm?id=will-it-float | doi=10.1038/scientificamerican0111-22}}</ref> When swimming, the thorax would be weighed down by the front legs, making it difficult for the animal to move its neck and legs in harmony<ref name = "swim"/><ref name="Naish"/> or keep its head above the surface.<ref name = "swim"/>
The [[IUCN]] lists the Columbian ground squirrel as a species of [[least concern]]. The reason for this listing is that the animal is widespread and common in its range and no major threats to the survival of the species are identified. Population trends are listed as stable.<!-- this section all same ref -->{{sfn|''IUCN Red List''|2016}} Similarly, the state of [[Montana]], considers Columbian ground squirrels an important part of the state's ecosystem, noting that the animals are abundant with a wide spread distribution and are not vulnerable through most of their range.<ref name="Montana Field Guide">{{cite web|title=Columbian Ground Squirrel – ''Urocitellus columbianus''|url=http://FieldGuide.mt.gov/speciesDetail.aspx?elcode=AMAFB05070|website=Montana Field Guide|publisher=Montana Natural Heritage Program and Montana Fish, Wildlife and Parks|access-date=5 March 2015}}</ref>
{{Clear}}
===Neck=References==
'''Footnotes:'''
[[File:Okapi Giraffe Neck.png|thumb|200px|Despite the vast difference in neck length the giraffe (right) and the okapi (left) both have seven cervical vertebrae.]]
{{Reflist|30em}}
The giraffe has an extremely elongated neck, which can be up to {{convert|2|m|abbr=on}} in length, accounting for much of the animal's vertical height.<ref name=Williams/>{{rp|29}} The long neck results from a disproportionate lengthening of the [[cervical vertebrae]], not from the addition of more vertebrae. Each cervical vertebra is over {{convert|28|cm|in|abbr=on}} long.<ref name=anatomy>{{cite book|author=Swaby, S.|year=2010|contribution=Giraffe|editor=Harris, T.|title=Mammal Anatomy: An Illustrated Guide|publisher=Marshall Cavendish Corporation|pages=64–84|isbn=0-7614-7882-5}}</ref>{{rp|71}} They comprise 52–54 percent of the length of the giraffe's [[vertebral column]], compared with the 27–33 percent typical of similar large ungulates, including the giraffe’s closest living relative, the [[okapi]].<ref name=bada>{{Cite journal | doi = 10.1111/j.1096-3642.2008.00458.x |last1=Badlangana |first1=L. N. |last2=Adams |first2=J. W. |last3=Manger |first3=P. R. | title = The giraffe ''(Giraffa camelopardalis)'' cervical vertebral column: A heuristic example in understanding evolutionary processes? | journal = Zoological Journal of the Linnean Society | volume = 155 | issue = 3 | pages = 736–57 | year = 2009}}</ref> This elongation largely takes place after birth, as giraffe mothers would have a difficult time giving birth to young with the same neck proportions as adults.<ref name=van>{{Cite journal | doi = 10.1002/jez.b.21353 |last1=Van Sittert |first1=S. J. |last2=Skinner |first2=J. D. |last3=Mitchell |first3=G. | title = From fetus to adult – An allometric analysis of the giraffe vertebral column | journal = Journal of Experimental Zoology Part B Molecular and Developmental Evolution | volume = 314B | issue = 6 | pages = 469–79 | year = 2010}}</ref> The giraffe's head and neck are held up by large muscles and a [[nuchal ligament]], which are anchored by long dorsal spines on the anterior [[thoracic vertebrae]], giving the animal a hump.<ref name="Dagg1971"/>
[[File:Flickr - Rainbirder - High-rise living.jpg|thumb|left|200px|An adult male giraffe feeding high up on an acacia]]
The giraffe's neck vertebrae have [[ball and socket joint]]s.<ref name=anatomy/>{{rp|71}} In particular, the [[Atlas (anatomy)|atlas]]–[[Axis (anatomy)|axis]] joint (C1 and C2) allows the animal to tilt its head vertically and reach more branches with the tongue.<ref name=Williams/>{{rp|29}} The point of articulation between the cervical and thoracic vertebrae of giraffes is shifted to lie between the first and second thoracic vertebrae (T1 and T2), unlike most other ruminants where the articulation is between the seventh cervical vertebra (C7) and T1.<ref name=bada/><ref name=van/> This allows C7 to contribute directly to increased neck length and has given rise to the suggestion that T1 is actually C8, and that giraffes have added an extra cervical vertebra.<ref>{{Cite journal|author=Solounias, N.|year=1999|title=The remarkable anatomy of the giraffe's neck|journal=Journal of Zoology|volume=247|issue=2|pages=257–68|doi=10.1111/j.1469-7998.1999.tb00989.x|url=http://www.ikhebeenvraag.be/mediastorage/FSDocument/73/download.pdf}}</ref> However, this proposition is not generally accepted, as T1 has other morphological features, such as an articulating [[rib]], deemed diagnostic of thoracic vertebrae, and because exceptions to the mammalian limit of seven cervical vertebrae are generally characterized by increased [[neurological disorder|neurological anomalies]] and maladies.<ref name=bada/>
'''Sources:'''
There are two main hypotheses regarding the evolutionary origin and maintenance of elongation in giraffe necks.<ref name=sim2010>{{Cite journal | doi = 10.1111/j.1469-7998.2010.00711.x |last1=Simmons |first1= R. E. |last2=Altwegg |first2=R. | title = Necks-for-sex or competing browsers? A critique of ideas on the evolution of giraffe | journal = Journal of Zoology | volume = 282 | issue = 1 | pages = 6–12 | year = 2010}}</ref> The "competing [[browsing (predation)|browsers]] hypothesis" was originally suggested by [[Charles Darwin]] and challenged only recently. It suggests that competitive pressure from smaller browsers, such as [[kudu]], [[steenbok]] and [[impala]], encouraged the elongation of the neck, as it enabled giraffes to reach food that competitors could not. This advantage is real, as giraffes can and do feed up to {{convert|4.5|m|abbr=on}} high, while even quite large competitors, such as kudu, can feed up to only about {{convert|2|m|abbr=on}} high.<ref name=dt1990>{{Cite journal | doi = 10.1111/j.1365-2028.1990.tb01136.x | last = du Toit | first = J. T. | title = Feeding-height stratification among African browsing ruminants | journal = African Journal of Ecology | volume = 28 | issue = 1 | pages = 55–62 | year = 1990 | url = http://courses.biology.utah.edu/goller/7406/Goller7406/duToitPdfs/Feedingheightstrat_1990.pdf}}</ref> There is also research suggesting that browsing competition is intense at lower levels, and giraffes feed more efficiently (gaining more leaf biomass with each mouthful) high in the canopy.<ref>{{Cite journal|author= Cameron, E. Z.; du Toit, J. T. | title = Winning by a Neck: Tall Giraffes Avoid Competing with Shorter Browsers| journal = American Naturalist | volume = 169| issue = 1| pages = 130–35| year = 2007| doi = 10.1086/509940 |pmid= 17206591 |url= http://www.cnr.usu.edu/files/uploads/faculty/winning_by_a_neck-du_Toit.pdf}}</ref><ref>{{Cite journal|author= Woolnough, A. P.; du Toit, J. T. | title = Vertical zonation of browse quality in tree canopies exposed to a size-structured guild of African browsing ungulates| journal = Oecologia | volume = 129| issue = 1| pages = 585–90| year = 2001| doi = 10.1007/s004420100771|url=http://courses.biology.utah.edu/goller/7406/Goller7406/duToitPdfs/Verticalzonation_2001.pdf}}</ref> However, scientists disagree about just how much time giraffes spend feeding at levels beyond the reach of other browsers,<ref name=sim1996/><ref name=sim2010/><ref name=dt1990/><ref name=sexdiff>{{Cite journal|author= Young, T. P.; Isbell, L. A. | title = Sex differences in giraffe feeding ecology: energetic and social constraints| journal = Ethology | volume = 87| issue = 1–2| pages = 79–89| year = 1991 |doi = 10.1007/s004420100771|url=http://tpyoung.ucdavis.edu/publications/1991GiraffesEthology.pdf}}</ref>
{{sfn whitelist|CITEREFThoringtonHoffman2005}}
and a 2010 study found that adult giraffes with longer necks actually suffered higher mortality rates under drought conditions than their shorter-necked counterparts. This study suggests that maintaining a longer neck requires more nutrients, which puts longer-necked giraffes at risk during a food shortage.<ref name="demography">{{cite journal|author=Mitchell, G.; van Sittert, S.; Skinner, J. D.|year=2010|title=The demography of giraffe deaths in a drought|journal=Transactions of the Royal Society of South Africa|volume=65|issue=
{{Refbegin}}
3|pages=165–68|doi=10.1080/0035919X.2010.509153}}</ref>
* {{cite book|last1=Bailey|first1=Vernon|last2=Bailey|first2=Florence Merriam|title=Wild animals of Glacier National Park|date=1918|publisher=Government Printing Office|___location=Washington|pages=45–49|url=https://archive.org/stream/wildanimalsofgla00unit#page/n5/mode/2up|access-date=21 February 2015}}
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*{{Cite journal|last=Barnes|first=Brian|date=1986|title=The Influence of Hibernation on Testis Growth and Spermatogenesis in the Golden-Mantled Ground Squirrel, Spermophilus Lateralis|url=https://www.academia.edu/19013846|journal=Biology of Reproduction|volume=35|issue=5 |pages=1289–1297|doi=10.1095/biolreprod35.5.1289 |pmid=3828438 |doi-access=free}}
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*{{cite journal|last1=Harris|first1=M. A.|title=Possible occurrence of inter-specific killing by a Columbian ground squirrel, ''Spermophilus columbianus''|journal=Canadian Field-Naturalist|date=1985|volume=99|issue=2|pages=250–252|url=https://www.biodiversitylibrary.org/page/28065267|access-date=1 March 2015}}
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* {{cite book|last1=Kurtén|first1=Björn|last2=Anderson|first2=Elaine|title=Pleistocene mammals of North America.|date=1980|publisher=Columbia University Press|___location=New York|isbn=0231037333}}
* {{cite iucn|author=Cassola, F.|year=2016|title=''Urocitellus columbianus''|volume=2016|page=e.T42466A22265632|doi=10.2305/IUCN.UK.2016-3.RLTS.T42466A22265632.en|access-date=30 July 2021|ref={{sfnRef|''IUCN Red List''|2016}}}}
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* {{cite book|last1=Richardson|first1=John|title=Fauna boreali-americana|date=1829|publisher=J. Murray|___location=London|url=https://archive.org/stream/faunaborealiamer01rich#page/160|access-date=20 February 2015}}
* {{cite book|last=Shaw|first=WT|title=California Ground Squirrels: A Bulletin Dealing with Life Histories, Habits and Control of the Ground Squirrels of California|chapter-url=https://books.google.com/books?id=CckyAQAAMAAJ&pg=PA710|access-date=1 March 2015|series=11, 12|volume=VII|year=1918|publisher=California state printing office|chapter=The Columbian ground squirrel (''Citellus columbianus columbianus'')}} <!-- {{sfn|Shaw|1918|p=}} -->
* {{Cite journal|last=Skibiel|first=Amy|date=2013|title=Milk composition in a hibernating rodent, the Columbian ground squirrel (Urocitellus columbianus)|journal=Journal of Mammalogy|volume=94|pages=146–154|doi=10.1644/1-MAMM-A-078.1 |s2cid=86280776 |doi-access=free}}
*{{cite journal|last1=Svihla|first1=Arthur|title=An Albino Columbian Ground Squirrel taken near Pullman, Washington|journal=The Murrelet|date=May 1932|volume=13|issue=2|page=55|jstor=3534104}}
* {{cite journal|last1=Svihla|first1=Arthur|title=Occurrence of a colony of albino ground squirrels near Pullman, Wash.|journal=The Murrelet|date=September 1933|volume=14|issue=3|page=78|jstor=3535311}}
* {{MSW3 Sciuridae | id = 12401015 | page = 806}}
* {{cite book <!-- I own hard copy of this book --Gaff -->|last1=Verts|first1=B.J.|last2=Carraway|first2=Leslie N|title=Land mammals of Oregon|url=https://books.google.com/books?id=8KI1AmzIDnwC|date=1998|publisher=University of California Press|___location=Berkeley|isbn=9780520211995|access-date=20 February 2015}}
*
*{{Cite journal|last=Young|first=P. J.|date=1990|title=Hibernating patterns of free-ranging Columbian ground squirrels|url=https://link.springer.com/article/10.1007/BF00317201|journal=Oecologia|volume=83|issue=4 |pages=504–511|doi=10.1007/BF00317201 |pmid=28313184 |bibcode=1990Oecol..83..504Y |s2cid=2681433 }}
*{{Refend}}
== Altri progetti ==
The other main theory, the [[sexual selection]] hypothesis, proposes that the long necks evolved as a secondary [[sexual dimorphism|sexual characteristic]], giving males an advantage in "necking" contests (see below) to establish dominance and obtain access to sexually receptive females.<ref name=sim1996>{{Cite journal|author=Simmons, R. E.; Scheepers, L. | title = Winning by a Neck: Sexual Selection in the Evolution of Giraffe| journal = The American Naturalist| volume = 148| issue = 5| pages = 771–86| year = 1996|url=http://bill.srnr.arizona.edu/classes/182/Giraffe/WinningByANeck.pdf|doi=10.1086/285955}}</ref> In support of this theory, necks are longer and heavier for males than females of the same age,<ref name=sim1996/><ref name=sim2010/> and the former do not employ other forms of combat.<ref name=sim1996/> However, one objection is that it fails to explain why female giraffes also have long necks.<ref>{{Cite journal|author= Mitchell, G.; van Sittert, S. J.; Skinner, J. D. | title = Sexual selection is not the origin of long necks in giraffes| journal = Journal of Zoology | volume = 278| issue = 4| pages = 281–86| year = 2009| doi=10.1111/j.1469-7998.2009.00573.x}}</ref>
{{interprogetto}}
===Internal systems===
[[File:Flickr - Rainbirder - Reticulated Giraffe drinking.jpg|thumb|left|Giraffe bending down to drink. A rete mirabile prevents excess blood flow to the brain when the neck is lowered.]]
In mammals, the left [[recurrent laryngeal nerve]] is longer than the right; in the giraffe it is over {{convert|30|cm|in|abbr=on}} longer. These nerves are longer in the giraffe than in any other living animal;<ref name="Wedel">{{Cite journal|author=Wedel, M. J.|year=2012|title=A monument of inefficiency: the presumed course of the recurrent laryngeal nerve in sauropod dinosaurs|journal=Acta Palaeontologica Polonica|volume=57|issue=2|pages=251–56|doi=10.4202/app.2011.0019|url=http://www.app.pan.pl/archive/published/app57/app20110019.pdf}}</ref> the left nerve is over {{convert|2|m|abbr=on}} long.<ref>{{cite book|author=Harrison, D. F. N.|year=1995|title=The Anatomy and Physiology of the Mammalian Larynx|publisher=Cambridge University Press|page=165|isbn=0-521-45321-6}}</ref> Each nerve cell in this path begins in the [[brainstem]] and passes down the neck along the [[vagus nerve]], then branches off into the recurrent laryngeal nerve which passes back up the neck to the larynx. Thus, these nerve cells have a length of nearly {{convert|5|m|abbr=on}} in the largest giraffes.<ref name="Wedel"/> The structure of a giraffe's brain resembles that of domestic cattle.<ref name=Williams/>{{rp|31}} The shape of the skeleton gives the giraffe a small lung volume relative to its mass.<ref name=SkinnerJD2011>{{Cite journal|author=Skinner, J. D.; Mitchell, G.|year= 2011|title= Lung volumes in giraffes, ''Giraffa camelopardalis''|journal= Comparative Biochemistry and Physiology – Part A: Molecular & Integrative Physiology|volume= 158|issue= 1|pages= 72–78|doi= 10.1016/j.cbpa.2010.09.003|url= http://137.215.9.22/bitstream/handle/2263/16472/Mitchell_Lung(2011).PDF?sequence=1}}</ref> Its long neck gives it a large amount of [[Dead space (physiology)|dead space]], in spite of its narrow windpipe. These factors increase the resistance to airflow. Nevertheless, the animal can still supply enough oxygen to its tissues.<ref name=SkinnerJD2011/>
[[File:Giraffe-Drinking-Nairobi.JPG|thumb|right|The giraffe's mouth while drinking]]
The [[circulatory system]] of the giraffe has several adaptations for its great height. Its heart, which can weigh more than {{convert|25|lb|kg|abbr=on|disp=flip}} and measures about {{convert|2|ft|cm|abbr=on|disp=flip|-1}} long, must generate approximately double the blood pressure required for a human to maintain blood flow to the brain. As such, the wall of the heart can be as thick as {{convert|7.5|cm|in|abbr=on}}.<ref name="Prothero 2003"/> Giraffes have unusually high heart rates for their size, at 150 beats per minute.<ref name=anatomy/>{{rp|76}} In the upper neck, a [[rete mirabile]] prevents excess blood flow to the brain when the giraffe lowers its head.<ref name= "MacDonald"/> The [[jugular vein]]s also contain several (most commonly seven) valves to prevent blood flowing back into the head from the [[inferior vena cava]] and [[right atrium]] while the head is lowered.<ref>{{cite journal|doi=10.3957/056.039.0210|author=Mitchell, G.; van Sittert, S. J.; Skinner, J. D.|title=The structure and function of giraffe jugular vein valves|journal= South African Journal of Wildlife Research|volume=39|issue=2|pages=175–80|url=http://137.215.9.22/bitstream/handle/2263/13994/Mitchell_Structure(2009).pdf?sequence=1 |year=2009}}</ref> Conversely, the blood vessels in the lower legs are under great pressure (because of the weight of fluid pressing down on them). To solve this problem, the skin of the lower legs is thick and tight; preventing too much blood from pouring into them.<ref name= "MacDonald"/>
Giraffes have [[Esophagus|oesophageal muscles]] that are unusually strong to allow regurgitation of food from the stomach up the neck and into the mouth for [[wikt:ruminate|rumination]].<ref name=anatomy/>{{rp|78}} They have four chambered stomachs, as in all ruminants, and the first chamber has adapted to their specialized diet.<ref name="Dagg1971"/> The giraffe's intestines measure up to {{convert|80|m|ft|abbr=on}} in length<ref name="Dagg1971"/> and have a relatively small ratio of small to large intestine.<ref>{{cite journal | author = Pérez, W.; Lima, M.; Clauss, M. | year = 2009 | title = Gross anatomy of the intestine in the giraffe (''Giraffa camelopardalis'') | url = | journal = Anatomia, Histologia, Embryologia | volume = 38 | issue = 6| pages = 432–35 | pmid = 19681830 | doi=10.1111/j.1439-0264.2009.00965.x}}</ref> The liver of the giraffe is small and compact.<ref name=anatomy/>{{rp|76}} A gallbladder is generally present during fetal life, but it may disappear before birth.<ref name="Dagg1971"/><ref>{{cite journal | author=Cave, A. J. E. | title=On the liver and gall-bladder of the Giraffe | journal=Proceedings of the Zoological Society of London | volume=120 | pages=381–93 | year=1950 | doi=10.1111/j.1096-3642.1950.tb00956.x | issue=2}}</ref><ref>{{cite journal | author1=Oldham-Ott, Carla K. |author2=Gilloteaux, Jacques | title=Comparative morphology of the gallbladder and biliary tract in vertebrates: variation in structure, homology in function and gallstones | journal=Microscopy Research and Technique | volume=38 | issue=6 | pages=571–79 | year=1997 | doi=10.1002/(SICI)1097-0029(19970915)38:6<571::AID-JEMT3>3.0.CO;2-I}}</ref>
==Behaviour and ecology==
===Habitat and feeding===
[[File:Giraffe feeding, Tanzania.jpg|thumb|Giraffe extending its tongue to feed. Its tongue, lips and palate are tough enough to deal with sharp thorns in trees.]]
Giraffes usually inhabit [[savanna]]s, [[grassland]]s and open [[woodland]]s. They prefer ''[[Acacia]]'', ''[[Commiphora]]'', ''[[Combretum]]'' and open ''[[Terminalia (plant)|Terminalia]]'' woodlands over denser environments like ''[[Brachystegia]]'' woodlands.<ref name=Kingdon1988/>{{rp|322}} The Angolan giraffe can be found in desert environments.<ref>{{cite thesis |author=Fennessy, J.|year=2004 |title=Ecology of desert-dwelling giraffe ''Giraffa camelopardalis angolensis'' in northwestern Namibia|publisher=[[University of Sydney]] |degree=[[Doctor of Philosophy|Ph.D.]] |url=http://ses.library.usyd.edu.au/handle/2123/910}}</ref> Giraffes browse on the twigs of trees, preferring trees of genera ''Acacia'', ''Commiphora'' and ''Terminalia'',<ref name=kingdon>{{Cite book|title=The Kingdon Field Guide to African Mammals|author=Kingdon, J.|publisher=Academic Press|pages=339–44|year=1997|isbn=0-12-408355-2}}</ref> which are important sources of calcium and protein to sustain the giraffe's growth rate.<ref name="Mitchell20003"/> They also feed on shrubs, grass and fruit.<ref name=Kingdon1988/>{{rp|324}} A giraffe eats around {{convert|34|kg|lb|abbr=on}} of foliage daily.<ref name=estes/> When stressed, giraffes may chew the bark off branches. Although [[herbivorous]], the giraffe has been known to visit carcasses and lick dried meat off bones.<ref name=Kingdon1988/>{{rp|325}}
During the wet season, food is abundant and giraffes are more spread out, while during the dry season, they gather around the remaining evergreen trees and bushes.<ref name=kingdon/> Mothers tend to feed in open areas, presumably to make it easier to detect predators, although this may reduce their feeding efficiency.<ref name=sexdiff /> As a [[ruminant]], the giraffe first chews its food, then swallows it for processing and then visibly passes the half-digested cud up the neck and back into the mouth to chew again.<ref name=anatomy/>{{rp|78–79}} It is common for a giraffe to salivate while feeding.<ref name=Williams/>{{rp|27}} The giraffe requires less food than many other herbivores because the foliage it eats has more concentrated nutrients and it has a more efficient digestive system.<ref name=kingdon/> The animal's feces come in the form of small pellets.<ref name="Dagg1971"/> When it has access to water, a giraffe drinks at intervals no longer than three days.<ref name=estes/>
Giraffes have a great effect on the trees that they feed on, delaying the growth of young trees for some years and giving "waistlines" to trees that are too tall.<ref name=estes/> Feeding is at its highest during the first and last hours of daytime. Between these hours, giraffes mostly stand and ruminate. Rumination is the dominant activity during the night, when it is mostly done lying down.<ref name=estes/>
[[File:Giraffa camelopardalis angolensis (mating).jpg|thumb|left|Male giraffe mounting a female. Generally, only dominant males are able to mate.]]
===Social life and breeding habits===
While giraffes are usually found in groups, the composition of these groups tends to be open and ever-changing.<ref name=Manyara>{{Cite journal|author= van der Jeugd, H. P; Prins, H. H. T. | title = Movements and group structure of giraffe (''Giraffa camelopardalis'') in Lake Manyara National Park, Tanzania| journal = Journal of Zoology | volume = 251| issue = 1| pages = 15–21| year = 2000| doi=10.1111/j.1469-7998.2000.tb00588.x|url=http://www.resource-ecology.org/publ/2000_Jeugd,Prins_MovementsAndGroupStructureOfGiraffeInLakeManyara.pdf}}</ref> They have few strong social bonds, and aggregations usually change members every few hours. For research purposes, a "group" has been defined as "a collection of individuals that are less than a kilometre apart and moving in the same general direction."<ref name= "Pratt 1985">{{cite journal | doi = 10.1080/00222938500770471 | author = Pratt D. M.; Anderson V. H. | year = 1985 | title = Giraffe social behavior | journal = Journal of Natural History | volume = 19 | issue = 4 | pages = 771–81 }}</ref> The number of giraffes in a group can range up to 32 individuals.<ref name=Manyara/> The most stable giraffe groups are those made of mothers and their young,<ref name= "Pratt 1985"/> which can last weeks or months.<ref name= "Leuthold 1979"/> Social cohesion in these groups is maintained by the bonds formed between calves.<ref name=Kingdon1988/>{{rp|330}}<ref name= "Pratt 1985"/> Mixed-sex groups made of adult females and young males are also known to occur.<ref name= "Pratt 1985"/> Subadult males are particularly social and will engage in playfights. However, as they get older males become more solitary.<ref name= "Leuthold 1979"/<ref name= "Leuthold 1979"/> Giraffes are not territorial,<ref name="Dagg1971"/> but they have [[home range]]s.<ref name=estes/> Male giraffes occasionally wander far from areas that they normally frequent.<ref name=Kingdon1988/>{{rp|329}}
Reproduction is broadly polygamous: a few older males mate with the fertile females. Male giraffes assess female fertility by tasting the female's urine to detect [[estrus]], in a multi-step process known as the [[flehmen response]].<ref name= "Pratt 1985"/><ref name= "Leuthold 1979">{{Cite journal|author=Leuthold, B. M.|year=1979|title=Social organization and behaviour of giraffe in Tsavo East National Park|journal=African Journal of Ecology|volume=17|issue=1|pages=19–34|doi=10.1111/j.1365-2028.1979.tb00453.x}}</ref> Males prefer young adult females over juveniles and older adults.<ref name= "Pratt 1985"/> Once an estrous female is detected, the male will attempt to court her. When courting, dominant males will keep subordinate ones at bay.<ref name= "Leuthold 1979"/> During copulation, the male stands on his hind legs with his head held up and his front legs resting on the female's sides.<ref name=estes/>
Although generally quiet and non-vocal, giraffes have been heard to communicate using various sounds. During courtship, males emit loud coughs.<ref name=estes/> Females call their young by bellowing. Calves will emit snorts, bleats, mooing and mewing sounds. Giraffes also snore, hiss, moan and make flute-like sounds,<ref name=estes/> and they communicate over long distances using [[infrasound]].<ref>{{cite web|title=Silent Sentinels?|publisher=PBS online – Nature|url=http://www.pbs.org/wnet/nature/episodes/tall-blondes/silent-sentinels/2256/|accessdate=21 December 2011}}</ref>
===Birthing and parental care===
[[File:Giraffe Family.jpg|thumb||Mother giraffe and calves feeding. It is mostly the females that raise young, and they may gather in nursery herds.]]
Giraffe [[gestation]] lasts 400–460 days, after which a single calf is normally born, although twins occur on rare occasions.<ref name=ap>{{Cite web|title=Mammal Guide – Giraffe|publisher=[[Animal Planet]]|url=http://animal.discovery.com/guides/mammals/habitat/tropgrassland/giraffe.html|accessdate=7 March 2009}}</ref> The mother gives birth standing up. The calf emerges head and front legs first, having broken through the [[fetal membrane]]s, and falls to the ground, severing the [[umbilical cord]].<ref name="Dagg1971"/> The mother then grooms the newborn and helps it stand up.<ref name=Williams/>{{rp|40}} A newborn giraffe is about {{convert|1.8|m|ft|abbr=on|sigfig=1}} tall. Within a few hours of birth, the calf can run around and is almost indistinguishable from a one-week-old. However, for the first 1–3 weeks, it spends most of its time hiding;<ref name="Langman 1977">{{Cite journal|author=Langman, V. A.|year=1977|title=Cow-calf relationships in giraffe (''Giraffa camelopardalis giraffa'')|journal=Zeitschrift fur Tierpsychologie|volume=43|issue=3|pages=264–86}} [[Digital object identifier|doi]]:[http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0310.1977.tb00074.x/abstract 10.1111/j.1439-0310.1977.tb00074.x]</ref> its coat pattern providing camouflage. The ossicones, which have lain flat while it was in the womb, become erect within a few days.<ref name=estes/>
Mothers with calves will gather in nursery herds, moving or browsing together. Mothers in such a group may sometimes leave their calves with one female while they forage and drink elsewhere. This is known as a "[[Crèche (zoology)|calving pool]]".<ref name= "Langman 1977"/> Adult males play almost no role in raising the young,<ref name=Kingdon1988/>{{rp|337}} although they appear to have friendly interactions.<ref name= "Pratt 1985"/> Calves are at risk of predation, and a mother giraffe will stand over her calf and kick at an approaching predator.<ref name=estes/> Females watching calving pools will only alert their own young if they detect a disturbance, although the others will take notice and follow.<ref name= "Langman 1977"/> The bond a mother shares with her calf varies, though it can last until her next calving.<ref name= "Langman 1977"/> Likewise, calves may suckle for only a month<ref name=Kingdon1988/>{{rp|335}} or as long as a year.<ref name=estes/><ref name= "Leuthold 1979"/> Females become sexually mature when they are four years old, while males become mature at four or five years. However, males must wait until they are at least seven years old to gain the opportunity to mate.<ref name=estes/><ref name=Williams/>{{rp|40}}
[[File:Giraffe Ithala KZN South Africa Luca Galuzzi 2004.JPG|thumb|left|Male giraffes will engage in necking to establish dominance.]]
===Necking===
Male giraffes use their necks as weapons in combat, a behaviour known as "necking". Necking is used to establish dominance and males that win necking bouts have greater reproductive success.<ref name=sim1996/> This behaviour occurs at low or high intensity. In low intensity necking, the combatants rub and lean against each other. The male that can hold itself more erect wins the bout.<ref name=estes/> In high intensity necking, the combatants will spread their front legs and swing their necks at each other, attempting to land blows with their ossicones. The contestants will try to dodge each other's blows and then get ready to counter. The power of a blow depends on the weight of the skull and the arc of the swing.<ref name=estes/> A necking duel can last more than half an hour, depending on how well matched the combatants are.<ref name=Kingdon1988/>{{rp|331}} Although most fights do not lead to serious injury, there have been records of broken jaws, broken necks, and even deaths.<ref name=sim1996/>
After a duel, it is common for two male giraffes to caress and court each other. Such interactions between males have been found to be more frequent than heterosexual coupling.<ref>{{Cite journal|author=Coe, M. J.|year=1967|title='Necking' behavior in the giraffe|journal=Journal of Zoology|volume=151|issue=2|pages=313–21|doi= 10.1111/j.1469-7998.1967.tb02117.x}}</ref> In one study, up to 94 percent of observed mounting incidents took place between males. The proportion of same-sex activities varied from 30–75 percent. Only one percent of same-sex mounting incidents occurred between females.<ref>{{Cite book|author=Bagemihl, B.|year= 1999|title=Biological Exuberance: Animal Homosexuality and Natural Diversity| publisher=St. Martin's Press| pages=391–93|isbn= 0-312-19239-8}}</ref>
===Mortality and health===
[[File:Lioness with giraffe kill, jackal lurking, kenya, august 9th 2012.jpg|thumb|right|Lioness seen with adult giraffe kill]]
Giraffes have an unusually long lifespan compared to other ruminants,<ref>{{Cite journal|author=Müller, D.W.; Zerbe, P; Codron, D; Clauss, M; Hatt, J.M.|year=2011|title=A long life among ruminants: giraffids and other special cases|journal=Schweizer Archiv für Tierheilkunde|volume=153|issue=11|pages=515–519|pmid=22045457|doi=10.1024/0036-7281/a000263}}</ref> up to 25 years in the wild.<ref name= "MacDonald"/> Because of their size, eyesight and powerful kicks, adult giraffes are usually not subject to predation.<ref name=estes/> However, they can fall prey to [[lion]]s and are regular prey for them in [[Kruger National Park]].<ref>{{Cite journal|author=Owen-Smith, N.; Mills, M. G.|year=2008|title= Predator-prey size relationships in an African large-mammal food web|journal=Journal of Animal Ecology|volume=77|issue=1|pages= 173–83|pmid= 18177336|url= http://137.215.9.22/bitstream/handle/2263/9023/Owen-Smith_Predator-prey(2008).pdf?sequence=1|doi=10.1111/j.1365-2656.2007.01314.x}}</ref> [[Nile crocodile]]s can also be a threat to giraffes when they bend down to drink.<ref name=Williams/>{{rp|31}} Calves are much more vulnerable than adults, and are additionally preyed on by [[leopard]]s, [[spotted hyena]]s and [[Lycaon pictus|wild dogs]].<ref name="Prothero 2003"/> A quarter to a half of giraffe calves reach adulthood.
Some parasites feed on giraffes. They are often hosts for [[tick]]s, especially in the area around the genitals, which has thinner skin than other areas.<ref name="Dagg1971"/> Tick species that commonly feed on giraffes are those of genera ''[[Hyalomma]]'', ''[[Amblyomma]]'' and ''[[Rhipicephalus]]''. Giraffes may rely on [[Red-billed Oxpecker|red-billed]] and [[yellow-billed oxpecker]]s to clean them of ticks and alert them to danger. Giraffes host numerous species of internal parasite and are susceptible to various diseases. They were victims of the (now eradicated) viral illness [[rinderpest]].<ref name="Dagg1971"/>
==Relationship with humans==
===History and cultural significance===
[[File:Giraffe cave art.jpg|thumb|[[San rock art]] in Namibia depicting a giraffe]]
Humans have interacted with giraffes for millennia. The [[San people]] of southern Africa have medicine dances named after some animals; the giraffe dance is performed to treat head ailments.<ref>{{Cite book|author=Ross, K.|year=2003|title=Okavango: jewel of the Kalahari|publisher=Struik|page=168|isbn=1-86872-729-7}}</ref> How the giraffe got its height has been the subject of various African [[Folklore|folktales]],<ref name=sim1996/> including one from eastern Africa which explains that the giraffe grew tall from eating too many magic herbs.<ref>{{cite book|author=Greaves, N.; Clement, R.|year=2000|title=When Hippo Was Hairy: And Other Tales from Africa|publisher=Struik|pages=86–88|isbn=1-86872-456-5}}</ref> Giraffes were depicted in art throughout the African continent, including that of the [[Kiffian culture|Kiffians]], [[Ancient Egypt|Egyptians]] and [[Meroë]] [[Nubia]]ns.<ref name=Williams>{{Cite book|author=Williams, E.|year=2011|title=Giraffe|publisher=Reaktion Books|isbn=1-86189-764-2}}</ref>{{rp|45–47}} The Kiffians were responsible for a life-size rock engraving of two giraffes that has been called the "world's largest rock art petroglyph".<ref name=Williams/>{{rp|45}}<ref>{{Cite web|url=http://www.bradshawfoundation.com/giraffe/|title=The Dabous Giraffe rock art petrograph|publisher=The Bradshaw Foundation|accessdate=6 November 2011}}</ref> The Egyptians gave the giraffe its own [[Egyptian hieroglyphs|hieroglyph]], named 'sr' in [[Old Egyptian language|Old Egyptian]] and 'mmy' in later periods.<ref name=Williams/>{{rp|49}} They also kept giraffes as pets and shipped them around the Mediterranean.<ref name=Williams/>{{rp|48–49}}
[[File:Tribute Giraffe with Attendant.jpg|thumb|left|Painting of a giraffe imported to China during the Ming dynasty]]
The giraffe was also known to the [[Ancient Greece|Greeks]] and [[Ancient Rome|Romans]], who believed that it was an unnatural hybrid of a [[camel]] and a leopard and called it ''camelopardalis''.<ref name=Williams/>{{rp|50}} The giraffe was among the many animals collected and displayed by the Romans. The first one in Rome was brought in by [[Julius Caesar]] in 46 BC and exhibited to the public.<ref name=Williams/>{{rp|52}} With the [[fall of the Western Roman Empire]], the housing of giraffes in Europe declined.<ref name=Williams/>{{rp|54}} During the [[Middle Ages]], giraffes were known to Europeans through contact with the Arabs, who revered the giraffe for its peculiar appearance.<ref name="Prothero 2003">{{Cite book|author=Prothero, D. R.; Schoch, R. M.|year=2003|title=Horns, Tusks, and Flippers: The Evolution of Hoofed Mammals|publisher=Johns Hopkins University Press|pages=67–72|isbn=0-8018-7135-2}}</ref>
In 1414, a giraffe was shipped from [[Malindi]] to [[Bengal]]. It was then [[Treasure voyages|taken to China]] by explorer [[Zheng He]] and placed in a [[Ming dynasty]] zoo. The animal was a source of fascination for the Chinese people, who associated it with the mythical [[Qilin]].<ref name=Williams/>{{rp|56}} The [[Medici giraffe]] was a giraffe presented to [[Lorenzo de' Medici]] in 1486. It caused a great stir on its arrival in [[Florence]].<ref>{{Cite journal|url=http://www.archive.org/download/ErikRingmaraudienceForAGiraffeEuropeanExceptionalismAndTheQuest_744/ErikRingmarAudienceForAGiraffe.pdf |title=Audience for a Giraffe: European Expansionism and the Quest for the Exotic|author= Ringmar, E.|journal= Journal of World History| year = 2006| volume = 17| issue = 4| pages = 353–97 |jstor = 20079397|doi=10.1353/jwh.2006.0060}}</ref> Another [[Zarafa (giraffe)|famous giraffe]] was brought from [[History of Egypt under the Muhammad Ali dynasty|Egypt]] to Paris in the early 19th century as a gift from [[Muhammad Ali of Egypt]] to [[Charles X of France]]. A sensation, the giraffe was the subject of numerous memorabilia or "giraffanalia".<ref name=Williams/>{{rp|81}}
Giraffes continue to have a presence in modern culture. [[Salvador Dalí]] depicted them with [[conflagration|conflagrated]] manes in some of his surrealist paintings. Dali considered the giraffe to be a symbol of masculinity, and a flaming giraffe was meant to be a "masculine cosmic apocalyptic monster".<ref name=Williams/>{{rp|123}} Several children's books feature the giraffe, including David A. Ufer's ''The Giraffe Who Was Afraid of Heights'', [[Giles Andreae]]'s ''Giraffes Can't Dance'' and [[Roald Dahl]]'s ''[[The Giraffe and the Pelly and Me]]''. Giraffes have appeared in animated films, as minor characters in [[Disney]]'s ''[[The Lion King]]'' and ''[[Dumbo]]'', and in more prominent roles in ''[[The Wild]]'' and in the ''[[Madagascar (franchise)|Madagascar]]'' films. [[Sophie the Giraffe]] has been a popular [[teether]] since 1961. Another famous fictional giraffe is the Toys "R" Us mascot [[Toys "R" Us#Geoffrey the Giraffe|Geoffrey the Giraffe]].<ref name=Williams/>{{rp|127}}
The giraffe has also been used for some scientific experiments and discoveries. Scientists have looked at the properties of giraffe skin when developing suits for [[astronaut]]s and [[fighter pilot]]s<ref name=anatomy/>{{rp|76}} because the people in these professions are in danger of passing out if blood rushes to their legs. Computer scientists have modeled the coat patterns of several subspecies using [[reaction–diffusion]] mechanisms.<ref>{{Cite journal|author=Walter, M.; Fournier, A.; Menevaux, D.|year=2001|title= Integrating shape and pattern in mammalian models in SIGGRAPH '01|journal=Proceedings of the 28th annual conference on Computer graphics and interactive techniques|pages= 317–26 |doi= 10.1145/383259.383294|url =http://www.csun.edu/~renzo/GraphicsResources/Articles/walter.pdf|isbn=1-58113-374-X}}</ref>
The [[constellation]] of [[Camelopardalis]], introduced in the seventeenth century, depicts a giraffe.<ref name=Williams/>{{rp|119–20}} The [[Tswana people]] of Botswana saw the constellation [[Crux]] as two giraffes – [[Acrux]] and [[Mimosa]] forming a male, and [[Gacrux]] and [[Delta Crucis]] forming the female.<ref>{{cite journal|author=Clegg, A.|year=1986|title=Some Aspects of Tswana Cosmology|journal=Botswana Notes and Records|volume=18|pages=33–37|jstor=40979758 }}</ref>
===Exploitation and conservation status===
[[File:Bundesarchiv Bild 105-DOA0377, Deutsch-Ostafrika, Giraffe.jpg|thumb|Giraffe killed by tribesmen in the early 20th century]]
Giraffes were probably common targets for hunters throughout Africa.<ref name=Kingdon1988/>{{rp|337}} Different parts of their bodies were used for different purposes.<ref name="Dagg1971"/> Their meat was used for food. The tail hairs served as [[flyswatter]]s, bracelets, necklaces and thread.<ref name=Kingdon1988/>{{rp|337}}<ref name="Dagg1971"/> Shields, sandals and drums were made using the skin, and the strings of musical instruments were from the tendons.<ref name="Dagg1971"/> The smoke from burning giraffe skins was used by the medicine men of [[Buganda]] to treat nose bleeds.<ref name=Kingdon1988/>{{rp|337}} The Humr people of Sudan consume the drink Umm Nyolokh; which is created from the liver and marrow of giraffes. Umm Nyolokh often contains DMT and other psychoactive substances from plants the giraffes eat such as Acacia; and is known to cause hallucinations of giraffes, believed to be the giraffes' ghosts by the Humr.<ref>{{cite journal|author=Ian Cunnison|title= Giraffe hunting among the Humr tribe|journal=Sudan Notes and Records|volume=39|year=1958}}</ref><ref>http://www.cracked.com/article/81_6-animals-that-can-get-you-high/</ref> In the 19th century, European explorers began to hunt them for sport.<ref name=Williams/>{{rp|129}} Habitat destruction has hurt the giraffe, too: in the [[Sahel]], the need for firewood and grazing room for livestock has led to [[deforestation]]. Normally, giraffes can coexist with livestock, since they do not directly compete with them.<ref name= "MacDonald"/>
The giraffe species as a whole is assessed as [[Least Concern]] from a conservation perspective by the [[International Union for Conservation of Nature|IUCN]], as it is still numerous. However, giraffes have been [[extirpated]] from much of their historic range including [[Eritrea]], [[Guinea]], [[Mauritania]] and [[Senegal]]. They may also have disappeared from [[Angola]], [[Mali]], and [[Nigeria]], but have been introduced to [[Rwanda]] and [[Swaziland]].<ref name=iucn/> Two subspecies, the [[West African giraffe]] and the [[Rothschild giraffe]], have been classified as [[Endangered species|Endangered]],<ref name=IUCNrothschildi/><ref name=IUCNperalta/> as wild populations of each of them number in the hundreds.<ref name=wildstatus/> In 1997, [[Jonathan Kingdon]] suggested that the [[Nubian giraffe]] was the most threatened of all giraffes;<ref name=kingdon/> {{as of|2010|lc=y}}, it may number fewer than 250, although this estimate is uncertain.<ref name=wildstatus/> Private game reserves have contributed to the preservation of giraffe populations in southern Africa.<ref name= "MacDonald"/> [[Giraffe Manor]] is a popular hotel in [[Nairobi]] that also serves as sanctuary for Rothschild's giraffes.<ref>{{cite web|author=Lord. M|date=11 January 2012|title=Outlandish Outposts: Giraffe Manor in Kenya|publisher=Forbes.com|accessdate=4 April 2012|url=http://www.forbes.com/sites/forbestravelguide/2012/01/11/outlandish-outposts-giraffe-manor-in-kenya/}}</ref> The giraffe is a protected species in most of its range. It is the [[national animal]] of Tanzania,<ref>{{Cite book |title=East Africa: Kenya, Tanzania & Uganda |author=Knappert, J |authorlink=Jan Knappert |year=1987 |publisher=Vikas Publishing House|isbn= 0-7069-2822-9 |page=57}}</ref> and is protected by law.<ref name="FoleyFoley2014">{{cite book|author1=Charles Foley|author2=Lara Foley|author3=Alex Lobora|author4=Daniela De Luca|author5=Maurus Msuha|author6=Tim R. B. Davenport|author7=Sarah M. Durant|title=A Field Guide to the Larger Mammals of Tanzania|url=http://books.google.com/books?id=dt6QAwAAQBAJ&pg=PA179|date=8 June 2014|publisher=Princeton University Press|isbn=978-1-4008-5280-2|pages=179–}}</ref> Unauthorised killing can result in imprisonment.<ref>{{cite web |url=http://tanzania.go.tz/home/pages/260 |title=National Symbols: National Animal |last1= |first1= |last2= |first2= |website=tanzania.go.tz |publisher=Tanzania Government Portal |accessdate=14 January 2015}}</ref> In 1999, it was estimated that over 140,000 giraffes existed in the wild, but estimates in 2010 indicate that fewer than 80,000 remain.<ref name=wildstatus/>
==Note==
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