In the comic strip, Peanuts by Charles M. Schulz, Snoopy was often stated to have seven siblings. Five appeared at various times in the strip: four brothers, Andy, Marbles, Olaf and Spike; and one sister, Belle. The two others were never mentioned by name in the comic strip. According to the TV special Snoopy's Reunion, their names are Molly and Rover; however, their appearance is not considered canonical in the comic strip. [1] In the June 6, 1959 comic strip, following the birth of Charlie Brown's sister Sally, Snoopy remarks that he has no brothers or sisters, and is an "only dog." This was later retconned to him being born in a litter of eight puppies. Their mother is called Missy, but has appeared only once in Peanuts, in the 1990s.
Spike
Spike by far appears most frequently. His appearance is similar to that of Snoopy, but he is substantially thinner, has a perpetually sleepy look, and sports a long, droopy mustache and a fedora. Spike lives alone in the desert near Needles, California, only occasionally interacting with the principal characters in the strip, generally in visiting Snoopy. His friends are mostly inanimate saguaro cacti. As the only saguaros in California are in the Whipple Mountains fifty miles south of Needles, Spike must live somewhere in this wilderness area. When he was introduced to the strip, it was revealed that Spike's exceptionally low weight was due to the fact that he had been living with coyotes, and his job was to clean out their den. Although he got a better-fed appearance after his first visit to the Brown household, he apparently had to go "back to business" soon after returning home, for he soon became as thin as before. He temporarily became Rerun's dog in I Want a Dog for Christmas, Charlie Brown, and also had a TV special, It's the Girl in the Red Truck, Charlie Brown, in which he was the primary character.
During a story arc in 1976, Spike is rescued by Snoopy and a group of Woodstock's friends, from a group of coyotes. The coyotes were apparently furious after Spike tried to sell them "Oceanfront Condos" in the desert of Needles. In 1983, Snoopy is convinced in a letter from Spike that the 1984 Olympics were being moved from Los Angeles to Needles. Snoopy, of course, comes to realize that the claim was false, after Spike admitted that his "friend," a cactus, had told him the rumor. Spike's last major storyline was in 1994, when he and his brothers Olaf and Andy visit Snoopy in the hospital. They leave shortly after Snoopy gets well.
Spike was used in on-off appearances sporadically through the rest of Peanuts history.
When Snoopy pretends to be a World War I Flying Ace, Spike is a soldier fighting in the trenches, though the only change in his appearance is that he wears an army helmet instead of a fedora for these appearances. When Spike became ill with influenza, Snoopy and Spike's mother Missy came over on a troopship to visit, wearing a fur hat (the soldiers manning the rails of the troopship were also beagles). This was her sole appearance in the strip.
Andy and Olaf
Andy and Olaf live together on a farm. Andy is distinguished by his shaggy dog appearance, but otherwise looks like Snoopy. Olaf appears to be somewhat overweight. He does not bear much resemblance to Snoopy or his other siblings. He also wears a hunting cap.
Olaf is first seen during a series in January 1989, in which he visits Snoopy. During this sequence, Lucy enters Olaf in an "ugly dog" contest, which he wins. He appears again in 1994, where he, Andy, and Spike visit Snoopy, who is in the hospital. After Snoopy gets better, the three brothers leave without saying good-bye. This is the first appearance of Andy in the strip.
After that Olaf and Andy are shown three times in 1994. They are sitting against a barn, contemplating what direction their lives should go in. They appear sporadically after that.
Andy and Olaf spent some time travelling to Needles to live with Spike. However, after "two right turns and twenty-three wrong ones" they eventually ended up back at Snoopy's doghouse. After a brief stay and failure to become Rerun's dogs, they continued to wander around and were considering buying banjos in their last appearance.
Notably, Andy is perhaps the only Peanuts character to have originated in animation before appearing in the strip - his animated debut was the 1991 TV special Snoopy's Reunion.
Belle
Belle is Snoopy's sister. She lives in Kansas City, Missouri with her unnamed teenage son who Snoopy noted as resembling the Pink Panther. Belle herself resembles her brother, but with longer eyelashes. She wears a lace collar.
Belle only made a few appearances in the strip, but is well-remembered because of the Belle stuffed animal toys sold in the late 1970s and early 1980s. Many people who were not regular readers of the comic strip mistakenly thought that she was Snoopy's girlfriend, rather than his sister.
In 1984, Snoopy and Belle inspired fashion designers around the world, including Lagerfeld, Armani, and de la Renta to create one-of-a-kind outfits in their honor. Both beagles modeled for the "Snoopy in Fashion" exhibition held that year in Japan.
Marbles
Marbles, reputedly the smartest of the siblings, is a spotted beagle whose one appearance in the comic strip was in a September 1982 story arc. He also appeared in the 1991 animated feature Snoopy's Reunion, and in a flashback from "I Want a Dog for Christmas, Charlie Brown", when Charlie Brown was talking to Rerun about Snoopy's siblings.
Other siblings
The two other siblings, Molly and Rover, appeared in the 1991 TV special Snoopy's Reunion; however, Schulz never depicted or named these characters in the comic strip, so these names are not considered to be canonical.