Aardvark (Orycteropus afer): Facts, Diet and Burrows

Appearance

An aardvark looks like a mix of several animals. It has a long, tube-like snout like a pig’s, long upright ears like a rabbit’s, a strongly arched back and a thick, tapering tail like a kangaroo’s. The skin is thick and tough, pale yellowish gray and thinly covered with coarse hair, and it is often stained reddish brown by the soil the animal digs in.

The legs are short and very muscular. Each front foot has four toes and each hind foot has five, and all of them carry large, flattened claws that are somewhere between a claw and a hoof. These work like spades. The eyes are small, but the ears can swivel independently and hearing is acute.

The snout ends in a flat disc with the nostrils. Dense hair around the nostrils and the ability to close them help keep out dust and insects while digging. The aardvark’s sense of smell is among the best of any mammal, supported by an unusually large number of turbinate bones inside the nose.

How big is an aardvark?

Aardvarks are about the size of a medium to large dog but much heavier for their length. Males and females are similar in size.

Habitat and range

Aardvarks live across most of Africa south of the Sahara, from Senegal and the Sahel east to Ethiopia and south to the Cape in South Africa. They are absent from Madagascar and avoid dense swamp forest, very rocky ground and some coastal deserts.

They need two things: soil soft enough to dig, and plenty of ants and termites. That combination is found in savannas, grasslands, open woodland, bushland and farmland. Aardvarks have been recorded from sea level to about 3,200 m (10,500 ft) in the Ethiopian highlands.

Diet and feeding

Aardvarks are specialist insect eaters. Almost all of their food is ants and termites, which they sniff out at night, dig out of nests and mounds with their claws, and lick up with a sticky tongue up to about 30 cm (12 in) long. An aardvark can eat tens of thousands of insects in one night; counts of up to about 50,000 have been reported.

The only plant food they are known to eat regularly is the aardvark cucumber, a melon-like fruit that ripens underground. The aardvark digs it up for its water and later spreads its seeds in its droppings. Aardvarks swallow insects with little chewing and grind them in a muscular part of the stomach that works like a gizzard. Read the full story in what do aardvarks eat?.

Burrows: homes for many animals

Digging is the center of aardvark life. An aardvark makes three kinds of holes: shallow scrapes made while feeding, temporary shelters scattered across its home range, and larger home burrows. A main burrow can be several meters long, with one or more entrances and a chamber at the end, and the longest recorded have been around 13 m (43 ft).

Aardvarks often move on and dig new burrows, leaving the old ones empty. These are quickly taken over by other animals, which is why the aardvark is sometimes called an ecosystem engineer. Warthogs, porcupines, hyenas, African wild dogs, jackals, mongooses, bats, owls, snakes and lizards all use old aardvark holes. In hot, dry places and during bush fires, these burrows give many smaller animals a cool, safe refuge. The common warthog is one of the best-known lodgers, often backing in so its tusks face the entrance.

Behavior

Aardvarks are mainly solitary and nocturnal. They spend the hot day underground and come out in the late afternoon or after dark. Before leaving the burrow, an aardvark often pauses at the entrance, listening and sniffing for danger, then bounds away from the hole before starting to forage.

At night an aardvark wanders along a zigzag route with its nose to the ground, usually covering a few kilometers and sometimes much more. It is a quiet animal, making soft grunts while feeding and a bleating sound when frightened. It is also a capable swimmer.

During cold or very dry spells, when insects are scarce, aardvarks may switch to feeding in the afternoon. In southern Africa, researchers have found that this shift is a warning sign of food stress.

Each aardvark uses a large home range with many burrows and feeding sites scattered across it. Ranges of neighbors can overlap, and the animals mark their presence with scent from glands and with droppings, which they bury in shallow holes. Mothers and their young are the only aardvarks that regularly share a burrow.

Because aardvarks are so hard to watch, much of what is known about their behavior comes from radio-tracking studies and, more recently, camera traps placed at burrow entrances. These cameras have shown just how many other species come and go from the same holes.

Reproduction and life cycle

Aardvarks meet only to mate. After a pregnancy of about seven months, the female gives birth to a single young, usually weighing about 1.7–1.9 kg (3.7–4.2 lb). The newborn is hairless and wrinkled, with soft, floppy ears.

The young stays in the burrow at first but begins following its mother on night trips at about two weeks old. It starts eating insects within a couple of months, is weaned at around three to four months, and can dig its own burrow by about six months. It often stays with its mother until the next young is born and becomes able to breed at about two years.

Aardvarks have lived up to about 23 years in captivity. Their lifespan in the wild is not well known.

Predators and defense

Lions, leopards, spotted hyenas and large pythons are the main predators of aardvarks. An aardvark’s first defense is to run in a zigzag or to dig: it can disappear underground remarkably fast and block the tunnel behind it with loose earth. If cornered, it fights back with powerful kicks and slashes of its claws, sometimes rolling onto its back to use all four feet.

Conservation status

The IUCN Red List classes the aardvark as Least Concern, last assessed in 2015, because it has a very large range and tolerates many habitats, including farmland. Numbers are hard to measure because the animals are so secretive. In some areas aardvarks are hunted for meat or traditional uses, and habitat loss has reduced them locally.

Climate change is a growing worry. During a severe drought in the Kalahari, researchers following tagged aardvarks found that most of them died as their insect food disappeared. Because aardvarks depend so heavily on ants and termites, hotter and drier conditions could hit them hard.

Is an aardvark an anteater?

Aardvarks share an ant-eating lifestyle with anteaters, pangolins and echidnas, and they were once called Cape anteaters or ant bears. But they belong to a different branch of the mammal family tree, the Afrotheria, which also includes elephants such as the African bush elephant. Their similarities are an example of convergent evolution. Learn more in is an aardvark an anteater?.

Teeth unlike any other mammal

Aardvarks are born with ordinary-looking incisors and canines at the front of the jaw, but these fall out early and are never replaced. Adults keep only a set of cheek teeth at the back of the mouth.

Each of these teeth is built from hundreds to about 1,500 slender, six-sided columns of dentine packed together like a bundle of drinking straws, each with its own tiny pulp canal. There is no enamel and no root. The teeth wear down steadily and keep growing throughout life. No other living mammal has teeth built this way, and they are the reason for the order’s name, Tubulidentata, meaning “tube teeth”.

Most ant-eating mammals, such as anteaters and pangolins, have lost their teeth completely. Some biologists suggest the aardvark kept its cheek teeth partly because it also chews the tough-skinned aardvark cucumber.

Myths and facts

Myth: the aardvark is a kind of pig. The name means “earth pig”, but the resemblance is skin deep. Pigs are hoofed mammals related to deer and whales, while the aardvark belongs to the African group Afrotheria.

Myth: aardvarks are anteaters. The two eat similar food and share some features, but they live on different continents and belong to different branches of the mammal family tree.

Fact: aardvarks help other animals survive. Their abandoned burrows give shelter to dozens of species, and their digging loosens and mixes the soil.

Fact: the aardvark is an alphabet favorite. Its double “a” puts it at or near the very beginning of many English dictionaries and animal A–Z books.

Aardvarks and people

In African folklore the aardvark is often admired for its hard work and its fearlessness against biting ants. In the English-speaking world, many people know it from Arthur, the aardvark hero of Marc Brown’s children’s books and the long-running animated series based on them. Aardvarks are also kept in many zoos, where visitors usually see them in nocturnal houses.