Orycteropus afer
aardvark

Aardvarks are found throughout sub-Saharan Africa, except for the West and Central rain forest regions. (Kingdon, 1997; Oxford University Press, 2009)

Aardvarks occupy grassland and savanna habitats in sub-Saharan Africa, preferring areas that have a large abundance of ants and termites year round. The location of their burrow may differ from where they forage, in which case they walk between the two sites at night. They are rarely found in areas that have hard, compact soil, rocky areas, or areas that frequently flood. They often live in temporary holes that are a few meters in length, but can also live in complex and intricate burrows, which can have eight or more entrances and extend as much as 6 meters underground. Burrow entrances are often plugged with a vent left at the top. (Kingdon, 1997; Lehmann, 2009; Oxford University Press, 2009)

Aardvarks are the size of small pigs, but have very thick skin and do not possess a fat layer. They are notable for their long nose, which is wider at the distal end, their squared-off head, and a tail that tapers off toward the tip. The body is massive and they have very muscular limbs ending in thick-nailed digits. The hair is short on the head, neck, and tail, but longer and darker on the rest of the body, especially the limbs. Hair is often worn off in adults, but apparent on the young. The sides of the face and tail are pale colored, lighter in females and darker in males. During the wet season, aardvarks have fat deposits that are likely fueled by termite consumption. (Kingdon, 1997; Knöthig, 2005; Oxford University Press, 2009)

Aardvarks have 4 toes on the forefeet and 5 toes on the hind feet, each ending in a spade-like claw that helps them to dig with great speed and force. Digging is used both to acquire food and as a means of escape. The stance is digitigrade. (Kingdon, 1997; Knöthig, 2005; Oxford University Press, 2009)

Aardvarks have peg-like molars and premolars, but no incisors or canines; the dental formula is 0/0 0/0 2/2 3/3. Their teeth lack enamel and are made up of densely packed tubules, composed of a modified form of dentine. The tubules are contained in a sleeve of dental cement. Embryos and infants have a full set of vestigial milk teeth, including canines. (Kingdon, 1997; Knöthig, 2005; Oxford University Press, 2009)

Aardvarks live for up to 18 years in the wild. In captivity, aardvarks are expected to live for about 23 years. (Knöthig, 2005)

Aardvarks are solitary, except when accompanied by young, and are very shy. Where aardvarks are most common, large and well-established burrows may be used by two or three animals. Aardvarks are rarely seen, rather their presence is indicated by their tracks, burrows, and scratch marks left by their powerful claws. Aardvarks forage at night, covering distances of 2 to 5 km each night. Before foraging, aardvarks leave their den in a ritualistic way. They first stop at the den opening to look for enemies, then run out, jump repeatedly, look around, and jump around more, before finally trotting off to forage. (Kingdon, 1997; Knöthig, 2005; Mutlow and Mutlow, 2008; Taylor and Skinner, 2003; Taylor, Lindsey, and Skinner, 2002)

Home Range

Aardvarks inhabit large home ranges (2 to 5 square kilometers) and are typically found in very low densities. (Kingdon, 1997)

The only known sounds made by aardvarks are grunts and, in cases of extreme fear, bleats. Both sexes have glands on their elbows and hips, which may aid in mating or spacing of individuals. However, scent marking has not been observed. (Kingdon, 1997; Knöthig, 2005)

Aardvarks have poor vision because their retinas contain only rods, which allow them to see at night, but leave them colorblind. They have a very acute sense of hearing and long ears that can be moved independently, as well as folded back and closed while tunneling. Aardvarks have an exceptional sense of smell due to structures in the nose that increase turbinal surface area, improving the detection of olfactory signals. The olfactory region of the brain is highly developed in aardvarks, giving the middle profile of the skull a swollen appearance.

Aardvarks eat at night and are myrmecophagous, i.e. they specialize on ants and termites, with the majority of their diet being ants. They dig rapidly into the sides or center of ant and termite nests or mounds, while feeding at the same time. The ants and termites are swept into their small mouth with their long, sticky tongue. Aardvarks swallow without chewing their food, or after chewing their food very little. The insects are digested in the pyloric region of the muscular, gizzard-like stomach. Some of the predator defenses that ants and termites use against myrmecophagous animals, such as pangolins, anteaters, and echidnas, include biting, stinging, chemical defenses, and building hard mounds. These defenses do not seem to affect aardvarks. Colonies of ants and termites are rarely destroyed after an aardvark feeds and can be built back up and reestablished. (Kingdon, 1997; Knöthig, 2005; Mutlow and Mutlow, 2008; Taylor and Skinner, 2003; Taylor, Lindsey, and Skinner, 2002)

If confronted by a predator, an aardvark will attempt to dig a hole in which to hide, taking about 10 minutes to completely cover itself up. If it cannot dig a hole, it will stand upright on its hind legs and tail, or lay on its back, and defend itself with its large front claws. Humans are the primary predator of aardvarks, but lions, hyenas, and leopards are also known to kill them. (Kingdon, 1997; Knöthig, 2005; Oxford University Press, 2009)

Aardvarks are important in their ecosystem because the holes they dig are used by a variety of other animals for shelter. These include hyenas, warthogs, squirrels, hedgehogs, mongooses, and bats, as well as birds and reptiles. (Kingdon, 1997; Knöthig, 2005; Oxford University Press, 2009)

Aardvark burrows can present a hazard for vehicles. (Kingdon, 1997; Knöthig, 2005)

Sometimes humans hunt aardvarks for their meat and hide, although products made out of aardvarks are subject to trade restrictions. Aardvarks may help control termite and ant populations, which are pests to humans. (Knöthig, 2005)

Aardvarks are widespread, however, they have been exterminated in many agricultural areas. They are vulnerable in all settled areas and endangered or extinct in areas with a high concentration of people. They are often hunted by farmers and ranchers who find their hole digging inconvenient or dangerous. Cultivation and pesticide use has resulted in the elimination of their food source in some areas. (Kingdon, 1997; Knöthig, 2005)

Recent studies based on DNA sequence analysis have placed aardvarks in a taxon referred to as Afrotheria. Other animals in this group include elephants, hyraxes, sirenians, elephant-shrews, golden moles, and tenrecs. Afrotherians are thought to have originated and evolved in Africa. Fossil records and morphology are beginning to support the molecular evidence. The order to which aardvarks belong, Tubulidentata, is unique because it is the only mammalian order that is represented by a single species. (Lehmann, 2009; Tabruce, Asher, and Lehmann, 2008)