The jackal is a member of any of three (sometimes four) small to medium-sized species of the family Canidae, found in Africa, Asia and southeastern Europe. Jackals fill a similar ecological niche to the coyote (the American jackal) in North America, that of predators of small to medium-sized animals, scavengers, and omnivores. Their long legs and curved canine teeth are adapted for hunting small mammals, birds and reptiles. Big feet and fused leg bones give them a long-distance runner's physique, capable of maintaining speeds of 16 km/h (9.9 mph) for extended periods of time. They are crepuscular, most active at dawn and dusk. In jackal society the social unit is that of a monogamous pair which defends its territory from other pairs. These territories are defended by vigorously chasing intruding rivals and marking landmarks around the territory with urine and feces. The territory may be large enough to hold some young adults who stay with their parents until they establish their own territory. Jackals may occasionally assemble in small packs, for example to scavenge a carcass, but normally hunt alone or as a pair.