Fennec Fox: The desert dwelling fennec is one of 12 species of vulpine foxes. It has the largest ears of any fox, in proportion to its body size, using its ears to cool itself and to detect the sounds of predator or prey.
A number of physical traits distinguish the canids. Intermediate in size among mammals, canids range from the tiny fennec, which weighs less than 2 kg (4 lb) to the imposingly large gray wolf, which can reach 80 kg (176 lb). Most canids have compact, fur-covered bodies and long, bushy tails. Many have a patch of dark fur on the top of the tail near its base, marking the position of a scent gland. Canids have a long, pointed snout and mouth. Their ears are usually erect, often pointed, and can be quite large in some species; bat-eared foxes, for example, were named for their conspicuously large, wide ears that better resemble those of a bat than a fox.
Arctic Fox: The arctic fox wears two coats. Its warm-weather coat is gray-brown. During the winter, however, its fur is a thick, white camouflage against a landscape of snow and ice, protection both from predators and from the harsh temperatures of tundra latitudes. The fox’s small snout and ears also conserve heat, as do its fur-covered feet, reminiscent of a rabbit’s. Temperatures drop to -70° C (-94° F) before the arctic fox begins to shiver. A small number have blue coloration in colder months, alternating to a rich brown in the summer.
Canids have a large number of powerfully built teeth used for killing and holding prey, in fighting, and in threat displays. While most canids have 42 teeth, some species such as bush dogs have only 38 teeth while bat-eared foxes have 50. Like humans, canids have different types of teeth that are distinguished by shape, position in the mouth, and function. The chisel-like incisors, used for cutting food and in grooming, are located in the front of the mouth. The incisors are followed by a pair of dagger-shaped canine teeth used in fighting and hunting. Premolars and molars, located near the back of the mouth, are used for grasping, slicing, and crushing meat and bone. The molars at the very back of the mouth are adapted for feeding on items such as insects, fruit, and leafy vegetation, as well as meat. Some canids include a high proportion of fruits, seeds, and other vegetable matter in their diets.
Dhole: The dhole or red dog, Cuon alpinus, hunts in packs and preys mainly upon mammals that are larger than itself, such as antelope and mountain sheep. Dholes are similar in size and shape to coyotes, but they can be distinguished by their ears, which have a more rounded shape.
All of the canids are excellent hunters, with keen senses of smelling and hearing, although their eyesight is not exceptional. They usually prey on mice and other rodents, rabbits, antelope, caribou, and deer—depending on their species and habitat. Canids are well adapted for long-distance pursuits of prey. They can run exceptionally fast and have remarkable endurance for covering long distances. For example, greyhounds have been clocked at 70 km/h (44 mph) and African hunting dogs can maintain speeds of 50 to 60 km/h (31 to 37 mph) for several kilometers.
A number of physical adaptations enable canids to maintain high speeds over great distances. They have long leg, wrist, and ankle bones and they are digitigrade—that is, they stand on their toes rather than on flat feet. These characteristics give canids a long stride that is further lengthened when the animal arches its backbone as it runs. Canids have small feet, and in most cases their feet have only four toes in contact with the ground. A small fifth toe, called the dewclaw, is usually present high up on both forefeet. All toes have strong, blunt claws. The small size and weight of their feet and limbs require less energy to move, enabling canids to run more efficiently than heavier-limbed animals.