Mouse-deer possess a triangular-shaped head, arched back, and round body with elevated rear quarters. The thin, short legs which support the mouse-deer are about the diameter of an average pencil. Although Java mouse-deer do not possess antlers or horns like regular deer, male Java mouse-deer have elongated, tusk-like upper canines which protrude downward from the upper jaw along the sides of their mouth. Males use these “tusks” to defend themselves and their mates against rivals.<ref name=superhero8>Nowak, R., J. Paradiso. 1983. Walker's Mammals of the World. Chicago: Johns Hopkins University Press.</ref> Females can be distinguished from males because they lack these prominent canines, and they are slightly smaller than the males.<ref name=eof5/> The average size of a Java mouse-deer ranges from {{Convert|1|-|2|kg}}, with females falling on the smaller end of this spectrum. Java mouse-deer can furthermore be distinguished by their lack of upper incisors. The coat coloration of the Java mouse-deer is reddish-brown with a white underside. Pale white spots or vertical markings are also present on the animal’s neck.<ref name=eof5/>
TheWith height of the Java mouse-deer is {{Convert|30|cm}} onan average.With average lengthslength of {{Convert|45|cm|abbr=on}} and an average tail lengthheight of {{Convert|530|cm|abbr=on}}, the Java mouse-deer is the smallest [[Neontology|extant]] (living) even-toed ungulate, as well as the smallest extant ungulate.<ref name=eof5/><ref name=erythrocytes9/>
JavaThe mouse-deer are [[endothermic]] and [[homoeothermic]], with an average basal metabolic rateweight of 4.883 W.<ref name=eof5/> Tragulus javanicus also possess the smallestJava [[erythrocytes]]mouse-deer ofranges thefrom mammalian species, and their erythrocytes are unique in that 12.8% of their erythrocytes have pits in them.<ref name=erythrocytes9>{{cite journal Convert| last1 = Fukuta 1| first1 = K. to| last2 = Kudo 2|kg}}, first2with =females H. | last3 = Jalaludin | first3 = S. | year = 1996 | title = Unique pitsfalling on the erythrocyteslower end of the lesserspectrum. mouse-deer,It Tragulushas javanicusan |average journaltail = Journallength of Anatomy {{Convert| volume = 189 5| issue = 1cm| pages abbr= 211–213 | pmc=1167845 | pmid=8771414on}}</ref>. Pitted erythrocytes are unique and have never been seen before physiologically or pathologically.The Java mouse-deer areis also considered to be the most primitive [[ruminantsruminant]] based on its behaviour and fossil records, thus theyit provideprovides thea living link between non-ruminants and ruminant speciesnon-ruminants.<ref name=animalrecs10>Carwardine, M., & London, E. (2007). Animal records. New York: Sterling</ref>
The Java mouse-deer is [[endothermic]] and [[homoeothermic]], and has an average basal metabolic rate of about 4.883 [[watt]]s.<ref name=eof5/> It also has the smallest [[red blood cell]]s of any mammal, and 12.8% of them have pits.<ref name=erythrocytes9>{{cite journal | last1 = Fukuta | first1 = K. | last2 = Kudo | first2 = H. | last3 = Jalaludin | first3 = S. | year = 1996 | title = Unique pits on the erythrocytes of the lesser mouse-deer, Tragulus javanicus | journal = Journal of Anatomy | volume = 189 | issue = 1| pages = 211–213 | pmc=1167845 | pmid=8771414}}</ref> Pitted red blood cells are unique and have not been seen before either physiologically or pathologically.
