Description
The aardvark is vaguely pig-like in appearance. Its body is stout with an arched back and is sparsely covered with coarse hairs. The limbs are of moderate length. The front feet have lost the pollex (or 'thumb'), resulting in four toes, while the rear feet have all five toes. Each toe bears a large, robust nail which is somewhat flattened and shovel-like, and appears to be intermediate between a claw and a hoof. The ears are disproportionately long, and the tail is very thick at the base and gradually tapers. The greatly elongated head is set on a short, thick neck, and the end of the snout bears a disc, which houses the nostrils. The mouth is small and tubular, typical of species that feed on termites. The aardvark has a long, thin, snakelike, protruding tongue and elaborate structures supporting a keen sense of smell.
An aardvark's weight is typically between 40 and 65 kilograms (88 and 140 lb). An aardvark's length is usually between 1 and 1.3 metres (3.3 and 4.3 ft), and can reach lengths of 2.2 metres (7 ft 3 in) when its tail (which can be up to 70 centimetres (28 in)) is taken into account. It is the largest member of the proposed clade Afroinsectiphilia. The aardvark is pale yellowish-gray in color and often stained reddish-brown by soil. The aardvark's coat is thin, and the animal's primary protection is its tough skin. The aardvark has been known to sleep in a recently excavated ant nest, which also serves as protection from its predators.
One of the most distinctive characteristics of the Tubulidentata is their teeth. Instead of having a pulp cavity, each tooth has a cluster of thin, upright, parallel tubes of vasodentin (a modified form of dentine), with individual pulp canals, held together by cementum. The teeth have no enamel coating and are worn away and regrow continuously. The aardvark is born with conventional incisors and canines at the front of the jaw, which fall out and are not replaced. Adult aardvarks have only cheek teeth at the back of the jaw, and have a dental formula of:
Genetically speaking, the aardvark is a living fossil, as its chromosomes are highly conserved, reflecting much of the early eutherian arrangement before the divergence of the major modern taxa.
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