Aardvark

The Aardvark (Orycteropus afer) is a medium-sized mammal native to Africa The name comes from the Dutch for "earth pig" (aarde earth, varken pig), because early settlers from Europe thought it resembled a pig (although Aardvarks are not closely related to pigs). more...

The Aardvark is the only surviving member of the family Orycteropodidae and of the order Tubulidentata. The Aardvark was originally placed in the same genus as the South American anteaters because of superficial similarities which, it is now known, are the result of convergent evolution, not common ancestry. (For the same reason, Aardvarks bear a striking first-glance resemblance to the marsupial bilbies and bandicoots of Australasia, which are not placental mammals at all.)

The oldest known Tubulidentata fossils have been found in Kenya and date to the early Miocene. Although the relationships of Tubulidentata are unknown, they are probably Ungulates. They spread to Europe and southern Asia during the later Miocene and early Pliocene periods. Three genera of the family Orycteropodidae are known: Leptorycteropus, Myorycteropus, and Orycteropus, the surviving Aardvark. A genus from Madagascar may be related to them, called Plesiorycteropus.

The most distinctive characteristic of the Tubulidentata is (as the name implies) their teeth which, instead of having a pulp cavity, have lots of thin tubes of dentine, each containing pulp and held together by cementum. The teeth have no enamel coating and are worn away and regrow continuously. Aardvarks are born with conventional incisors and canines at the front of the jaw, but these fall out and are not replaced. In adult Aardvarks, the only teeth are the molars at the back of the jaw.

Aardvarks are only vaguely pig-like; the body is stout with an arched back; the limbs are of moderate length. The front feet have lost the pollex (or 'thumb')—resulting in four toes—but 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 very thick at the base with a gradual taper. The greatly elongated head is set on a short, thick neck, and at the end of the snout is a disk in which the nostrils open. The mouth is typical of species that feed on termites: small and tubular. Aardvarks have long, thin, protrusible tongues and elaborate structures supporting a keen sense of smell.

Weight is typically between 40 and 65kg; length is usually between 1 and 1.3m. Aardvarks are a pale yellowish gray in color, often stained reddish-brown by soil. The coat is thin and the animal's primary protection is its tough skin; Aardvarks have been known to sleep in a recently excavated ant nest, so well does it protect them.

In the past, several individual species of Aardvark were named, however current knowledge indicates that there is only one species, Orycteropus afer, with several subspecies; 18 have been listed but most are regarded as invalid.

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