Further systematic comments occur in the generic accounts. Fennecus zerda is the smallest species, and Canis lupus is the largest. In a given population, males generally average larger than females. There are four digits on the hind foot and five on the forefoot, except in Lycaon, which has four on both the front and the back foot. The claws are blunt.
Males have a well-developed baculum, and females generally have three to seven pairs of mammae.
The skull is elongate. The bullae are prominent but usually are not highly inflated. For dens they may use burrows, caves, crevices, or hollow trees. These alert, cunning animals may be diurnal, nocturnal, or crepuscular. They are generally active throughout the year.