Wolves, foxes and wild dogs in U.S. zoos

What makes a canid

All canids share a similar basic form, best shown by the gray wolf, though the length of the muzzle, legs, ears and tail varies widely between species. They are digitigrade, walking on their toes, and their claws are blunt and non-retractile in some species and sharper and partly retractile in others. Strong molar teeth let most species crack bone to reach the marrow.

Social life ranges from solitary to highly cooperative. Gray wolves and other larger canids live in packs, which let them tackle larger prey, and in most packs only the breeding male and female reproduce. Canids are typically monogamous and fathers help raise the young.

Wolves, coyotes and wild dogs

The genus Canis includes the gray wolf of Eurasia and North America, the coyote and the red wolf. The African wild dog is the only living member of its genus, Lycaon. It lives in permanent packs and runs prey down with stamina and teamwork rather than a single sprint, and adults regurgitate food not only for pups but for other adults too. Its patchy coat of black, brown, yellow and white differs from animal to animal.

South America has its own canids. The maned wolf is the largest canine native to the continent, standing up to 110 cm (43 in) at the withers, yet it hunts alone, tapping the ground with a front foot to flush prey from tall grass.

Telling the foxes apart

Foxes typically have a triangular face, pointed ears, a long snout and a bushy tail. Desert foxes have large ears and short fur that help them stay cool. The fennec fox has the greatest ear-to-body ratio of any canid, and its ears both shed heat and pick up prey moving underground. The bat-eared fox of eastern and southern Africa uses its 11 to 13 cm (4.3 to 5.1 in) ears to find harvester termites, which can make up 80 to 90 percent of its diet.

The red fox is the most common and widespread fox, usually auburn with a white-tipped tail. The gray fox, found from southern Canada to Colombia and Venezuela, is one of the few tree-climbing canids.

Conservation picture

Many canids are widespread, but some are in real trouble. The red wolf is Critically Endangered: its last wild animals were brought into captivity in the 1970s, bred, and reintroduced to eastern North Carolina in 1987, and that population of around 30 is the only one in the wild. The African wild dog has been listed as Endangered on the IUCN Red List since 1990, and the maned wolf is Near Threatened.