Overview

The aardvark (/ˈɑːrdvɑːrk/ ARD-vark; Orycteropus afer) is a medium-sized, burrowing, nocturnal mammal native to Africa. It is the only living species of the order Tubulidentata, although other prehistoric species and genera of Tubulidentata are known. Unlike other insectivores, it has a long pig-like snout, which is used to sniff out food. It roams over most of the southern two-thirds of the African continent, avoiding areas that are mainly rocky. A nocturnal feeder, it subsists on ants and termites, which it will dig out of their hills using its sharp claws and powerful legs. It also digs to create burrows in which to live and rear its young. It receives a "least concern" rating from the IUCN, although its numbers seem to be decreasing.

Naming

The aardvark is sometimes colloquially called "African ant bear", "anteater" (not to be confused with the South American anteater), or the "Cape anteater" after the Cape of Good Hope. The name "aardvark" (Afrikaans pronunciation: [ˈɑːrtfark]) comes from earlier Afrikaans (erdvark) and means "earth pig" or "ground pig" (aarde: earth/ground, vark: pig), because of its burrowing habits. The name Orycteropus means burrowing foot, and the name afer refers to Africa. The name of the aardvarks's order, Tubulidentata, comes from the tubule-style teeth.

Taxonomy

The aardvark is not closely related to the pig; rather, it is the sole extant representative of the obscure mammalian order Tubulidentata, in which it is usually considered to form one variable species of the genus Orycteropus, the sole surviving genus in the family Orycteropodidae. The aardvark is not closely related to the South American anteater, despite sharing some characteristics and a superficial resemblance. The similarities are based on convergent evolution. The closest living relatives of the aardvark are the elephant shrews, tenrecs and golden moles. Along with the sirenians, hyraxes, elephants, and their extinct relatives, these animals form the superorder Afrotheria. Studies of the brain have shown the similarities with Condylarthra, and given the clade's status as a wastebasket taxon it may mean some species traditionally classified as "condylarths" are actually stem-aardvarks.

Evolutionary history

Based on fossils, Bryan Patterson has concluded that early relatives of the aardvark appeared in Africa around the end of the Paleocene. The ptolemaiidans, a mysterious clade of mammals with uncertain affinities, may actually be stem-aardvarks, either as a sister clade to Tubulidentata or as a grade leading to true tubulidentates.

The first unambiguous tubulidentate was probably Myorycteropus africanus from Kenyan Miocene deposits. The earliest example from the genus Orycteropus was Orycteropus mauritanicus, found in Algeria in deposits from the middle Miocene, with an equally old version found in Kenya. Fossils from the aardvark have been dated to 5 million years, and have been located throughout Europe and the Near East.

The mysterious Pleistocene Plesiorycteropus from Madagascar was originally thought to be a tubulidentate that was descended from ancestors that entered the island during the Eocene. However, a number of subtle anatomical differences coupled with recent molecular evidence now lead researchers to believe that Plesiorycteropus is a relative of golden moles and tenrecs that achieved an aardvark-like appearance and ecological niche through convergent evolution.