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Lifespan, longevity, and ageing

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Maximum longevity: 29.8 years (captivity) Observations: One captive specimen lived for 29.8 years (Richard Weigl 2005).
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Associations

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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.

Known Predators:

  • humans (Homo sapiens)
  • lions (Panthera leo)
  • hyenas (Hyaenidae)
  • leopards (Panthera pardus)
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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Morphology

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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.

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.

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.

Range mass: 40 to 82 kg.

Range length: 100 to 158 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger; sexes colored or patterned differently

Average basal metabolic rate: 34.275 W.

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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Life Expectancy

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

Average lifespan
Status: wild:
18 years.

Average lifespan
Status: captivity:
23 years.

Average lifespan
Sex: male
Status: captivity:
24.0 years.

Average lifespan
Status: captivity:
10.0 years.

Average lifespan
Status: captivity:
23.0 years.

Average lifespan
Status: wild:
23.0 years.

Average lifespan
Sex: female
Status: captivity:
18.0 years.

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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Habitat

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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.

Habitat Regions: temperate ; tropical ; terrestrial

Terrestrial Biomes: savanna or grassland

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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Distribution

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Aardvarks are found throughout sub-Saharan Africa, except for the West and Central rain forest regions.

Biogeographic Regions: ethiopian (Native )

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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Trophic Strategy

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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.

Animal Foods: insects

Primary Diet: carnivore (Insectivore )

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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Untitled

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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.

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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Behavior

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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.

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.

Communication Channels: acoustic ; chemical

Other Communication Modes: pheromones

Perception Channels: visual ; tactile ; acoustic ; chemical

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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Conservation Status

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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.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Benefits

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Aardvark burrows can present a hazard for vehicles.

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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Barbara Lundrigan, Michigan State University
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Benefits

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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.

Positive Impacts: food ; body parts are source of valuable material; controls pest population

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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Associations

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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.

Ecosystem Impact: creates habitat; soil aeration

Mutualist Species:

  • hyenas (Hyaenidae)
  • warthogs (Phacochoerus)
  • squirrels (Sciuridae)
  • hedgehogs (Erinaceidae)
  • mongooses (Herpestidae)
  • bats (Chiroptera)
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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Barbara Lundrigan, Michigan State University
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Tanya Dewey, University of Michigan-Ann Arbor
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Reproduction

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Aardvarks are solitary and territorial, coming together only to breed. They are believed to be polygynous.

Mating System: polygynous

Male aardvarks have genitals that secrete a powerful musk and both males and females have glands on their elbows and hips. These glands might help with individual spacing and/or be involved in mating, but obvious scent marking has not been reported. Northern African aardvarks give birth between October and November, while aardvarks in South Africa give birth between May and July.

Usually one young is born after a gestation period of about 7 months. Offspring are born naked and with eyes open. The young begin to follow their mother at 2 weeks. They nurse until 3 months, at which time they begin to eat insects. At about 6 months, they become independent of the mother, and at about 2 years, they become sexually active. Aardvarks live to be about 18 years of age.

Breeding interval: Aardvarks breed once yearly

Breeding season: It is believed that aardvarks breed earlier in the year the closer they are to they equator.

Range number of offspring: 1 to 2.

Average number of offspring: 1.

Average gestation period: 7 months.

Average weaning age: 3 months.

Average time to independence: 6 months.

Average age at sexual or reproductive maturity (female): 2 years.

Average age at sexual or reproductive maturity (male): 2 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous

Average birth mass: 1800 g.

Average gestation period: 225 days.

Average number of offspring: 1.

Average age at sexual or reproductive maturity (male)
Sex: male:
730 days.

Average age at sexual or reproductive maturity (female)
Sex: female:
730 days.

Female aardvarks give birth in their burrow and the young remain underground for several weeks, while maturing. Offspring are taken care of by the mother until they are independent at about 6 months, after which they dig their own burrows.

Parental Investment: altricial ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Protecting: Female)

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Ratzloff, E. 2011. "Orycteropus afer" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Orycteropus_afer.html
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Elizabeth Ratzloff, Michigan State University
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Barbara Lundrigan, Michigan State University
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Tanya Dewey, University of Michigan-Ann Arbor
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Biology

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The elusive aardvark is primarily a nocturnal animal (1), spending the day curled up in its burrow asleep (5). However, it can occasionally be spotted venturing outside in the daylight on a cold afternoon (1), or early in the morning when it may sun itself by the burrow's entrance (5). At night the aardvark leaves the safety of its burrow and begins its search for food (5). It feeds almost exclusively on a smorgasbord of ant and termite species (3), and will forage for its meal by travelling in a zigzag path, inspecting a strip of ground about 30 metres wide with its snout (5). The aardvark tends to walk on its claws, somewhat slowly and awkwardly, and on soft ground its dragging tail leaves a trail behind (5). Once the aardvark has located its food, either after digging into the ground, tearing into a termite nest, or finding an army of ants on the march (5), the aardvark gathers its prey with its long, sticky tongue, which can extend to a remarkable 30 centimetres (5). It does not chew its insect prey, of which it can eat over 50,000 each night, but instead swallows it whole and grinds it up in a muscular area of its lower stomach (3). Digging is a central feature of the aardvark's life, and an activity that it is incredibly adept at. Not only does it dig shallow holes in search of food, it also digs burrows, measuring up to three metres long (5), for daytime rest and to escape predators (1), and also excavates extensive tunnel systems in which it gives birth to its young. These may be up to 13 metres long, with numerous chambers and multiple entrances (5). Its powerful limbs and sharp, spoon-shaped claws make easy work of digging (3), even in hard, stone-baked ground, and it can dig a hole faster than several men with shovels (5). The burrows of the aardvark are used by numerous other African animals, from invertebrates to mammals, making the aardvark an important species in the ecosystems in which it is found (1). The aardvark is a largely solitary animal and is only occasionally seen in the company of other individuals (1), presumably for mating and when a young accompanies its mother (5). The gestation period in this species lasts for between seven and nine months, resulting in the birth of a single, naked, flesh-coloured young. The young aardvark will remain in the burrow for about two weeks before starting to accompany its mother on night time foraging trips. By the age of six months, the young can dig for itself, and by 12 months it has reached the size of an adult. Sexual maturity is obtained at about two years of age (5).
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Conservation

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Throughout its vast range, the aardvark occurs in a number of protected areas (1). Aside from this, the aardvark is not believed to be in any need of conservation action (1). The aardvark plays such a vital role in many ecosystems, creating burrows for other animals and even limiting the enormous damage that termites can inflict on our crops (5), that hopefully the aardvark will remain unthreatened for the foreseeable future.
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Description

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While this bizarre and elusive mammal may look similar in appearance to a pig, (aardvark literally means 'earthpig' in Afrikaans (3)), it is actually the only member of the order Tubulidentata (2). The aardvark has a stocky, arched body sparsely covered with bristly hair, a short neck, a long and muscular tail and long, pointed ears (2). Like a pig, the aardvark also has a flexible, tubular snout, although much longer than its namesake's, and a long, extensible tongue, which together are perfectly suited to searching out and consuming a diet of ants and termites (3) (4). The thick skin of the aardvark ranges in colour from pale yellowish-grey to pinkish (4) (5), although this is often stained darker grey or reddish-brown from the soil in which it burrows (4). Its short, powerful limbs bear large, sharp, shovel-shaped claws, four on the forefeet, five on each hindfoot, which enable the aardvark to dig with ease (2).
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Habitat

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Within its large range, the aardvark occurs in a great variety of habitats, including grasslands, rainforests, savanna and woodland, with its presence largely dictated by the distribution of suitable ant and termite species (1). It shows a preference for areas of sandy soil (5), and will avoid rocky ground that is hard to dig in and habitats that are extremely dry (1).
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Range

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The aardvark is widely distributed in Africa south of the Sahara, from Senegal, east to Ethiopia and south to South Africa (1), although it is absent from the Namib Desert (1).
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Status

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Classified as Least Concern (LC) on the IUCN Red List (1).
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Threats

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Although overall, due to its widespread distribution, the global population of the aardvark is not considered to be threatened, in some areas numbers have been reduced as a result of human activities (1). Certain populations in eastern, central and western Africa are thought to be declining, as a growing human population destroys suitable habitat and hunts the aardvark for its meat. The skin, claws and teeth are also used to make bracelets, charms and curios (1), and even the aardvark's bristly hair is reportedly sometimes reduced to a powder and regarded as a potent poison when added to the local beer (3). Aardvark habitat is most often lost to agriculture (1), with intensive crop farming resulting in a decline in aardvark numbers (3). However, not all agriculture has a negative impact on the aardvark; cattle herding may actually benefit this species, as cattle-trampled ground creates the right conditions for termites (3). Conflict may also arise when agriculture encroaches onto aardvark habitat, as burrows can damage farming equipment, roads, dam walls, and fences, and the aardvark may be persecuted by farmers as a result (5) (6). Ironically, in areas where the aardvark and other insect-eating animals have been exterminated, pasture and cereal crops have suffered massive damage from termites (5).
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The Aardvark according to MammalMAP

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The Aardvark (Orycteropus afer) can be found in sub-Saharan Africa in a broad range of habitats, including grasslands, savannah, woodlands and even semi-arid areas, anywhere water and termites are in abundance.

Aardvarks have stocky, pinkish-grey bodies with little hair, a short neck and a strongly arched back. They have powerful legs covered with dark fur. While their hind feet have five digits, their forefeet only have four, with long claw-like nails used for digging out burrows. Attached to their elongated heads are long, tubular ears, normally sticking upright. Their snouts are long and narrow with nostrils that can be sealed. They have a short and muscular, cone-shaped tail, tapering to a point.

Don’t try looking for these elusive animals during the day, as they are mostly nocturnal, only showing face during the day to soak up heat from the sun.

With a tongue up to 30 cm long, aardvarks feed almost exclusively on termites and ants, and get most of their food from underground. During the day they rest in their burrows, which they also use to escape predators. These burrowing mammals can dig 60 cm deep in 15 seconds!

Aardvarks are solitary animals, only coming together occasionally for very short periods. They give birth only once a year, and have no specific breeding season.

Interesting facts:

Aardvarks are good swimmers!

They grunt and bleat when threatened.

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Aardvark

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Skeleton of an aardvark

The aardvark (/ˈɑːrdvɑːrk/ ARD-vark; Orycteropus afer) is a medium-sized, burrowing, nocturnal mammal native to Africa.[2][3] It is the only living species of the order Tubulidentata,[4][5] although other prehistoric species and genera of Tubulidentata are known. Unlike most other insectivores, it has a long snout, similar to that of a pig, which is used to sniff out food.

The aardvark is found over much 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. The animal is listed as "least concern" by the IUCN, although its numbers are decreasing. Aardvarks are afrotheres, a clade which also includes elephants, manatees, and hyraxes.

Name and taxonomy

Name

The aardvark is sometimes colloquially called the "African ant bear",[6] "anteater" (not to be confused with the South American anteater), or the "Cape anteater"[6] after the Cape of Good Hope. The name "aardvark" is Afrikaans (Afrikaans pronunciation: [ˈɑːrtfark]), comes from earlier Afrikaans erdvark[6] and means "earth pig" or "ground pig" (aarde: "earth", vark: "pig"), because of its burrowing habits.[7][8][9] The name Orycteropus means "burrowing foot", and the name afer refers to Africa.[10] The name of the aardvark's order, Tubulidentata, comes from the tubule-style teeth.[11]

Taxonomy

Skull of an aardvark

The aardvark is not closely related to the pig; rather, it is the sole extant representative of the obscure mammalian order Tubulidentata,[10] 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.[12] The similarities are the outcome of convergent evolution.[13] The closest living relatives of the aardvark are the elephant shrews, tenrecidae, and golden moles.[14] Along with sirenians, hyraxes, elephants,[15] and their extinct relatives, these animals form the superorder Afrotheria.[16] Studies of the brain have shown the similarities with Condylarthra,[13] 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.[13][17] 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.[18][19]

The first unambiguous tubulidentate was probably Myorycteropus africanus from Kenyan Miocene deposits.[13] 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.[13] Fossils from the aardvark have been dated to 5 million years, and have been located throughout Europe and the Near East.[13]

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.[20]

Subspecies

The aardvark has seventeen poorly defined subspecies listed:[4]

  • Orycteropus afer afer
  • O. a. adametzi Grote, 1921
  • O. a. aethiopicus Sundevall, 1843
  • O. a. angolensis Zukowsky & Haltenorth, 1957
  • O. a. erikssoni Lönnberg, 1906
  • O. a. faradjius Hatt, 1932
  • O. a. haussanus Matschie, 1900
  • O. a. kordofanicus Rothschild, 1927
  • O. a. lademanni Grote, 1911
  • O. a. leptodon Hirst, 1906
  • O. a. matschiei Grote, 1921
  • O. a. observandus Grote, 1921
  • O. a. ruvanensis Grote, 1921
  • O. a. senegalensis Lesson, 1840
  • O. a. somalicus Lydekker, 1908
  • O. a. wardi Lydekker, 1908
  • O. a. wertheri Matschie, 1898

The 1911 Encyclopædia Britannica also mentions O. a. capensis or Cape ant-bear from South Africa.[21]

Description

An aardvark skeleton and mounted individual

The aardvark is vaguely pig-like in appearance. Its body is stout with a prominently arched back[22] and is sparsely covered with coarse hairs. The limbs are of moderate length, with the rear legs being longer than the forelegs.[16] 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. Whereas the aardvark is considered digitigrade, it appears at times to be plantigrade. This confusion happens because when it squats it stands on its soles.[22] A contributing characteristic to the burrow digging capabilities of aardvarks is an endosteal tissue called compacted coarse cancellous bone (CCCB). The stress and strain resistance provided by CCCB allows aardvarks to create their burrows, ultimately leading to a favorable environment for plants and a variety of animals.[23][24]

An aardvark's weight is typically between 60 and 80 kilograms (130–180 lb).[16] An aardvark's length is usually between 105 and 130 centimetres (3.44–4.27 ft),[5] 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 60 centimetres (24 in) tall at the shoulder, and has a girth of about 100 centimetres (3.3 ft).[22] 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. Its hair is short on its head and tail; however its legs tend to have longer hair.[5] The hair on the majority of its body is grouped in clusters of 3-4 hairs.[22] The hair surrounding its nostrils is dense to help filter particulate matter out as it digs. Its tail is very thick at the base and gradually tapers.

Head

The greatly elongated head is set on a short, thick neck, and the end of the snout bears a disc, which houses the nostrils. It contains a thin but complete zygomatic arch.[22] The head of the aardvark contains many unique and different features. 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, hexagonal, upright, parallel tubes of vasodentin (a modified form of dentine), with individual pulp canals, held together by cementum.[16] The number of columns is dependent on the size of the tooth, with the largest having about 1,500.[13] The teeth have no enamel coating and are worn away and regrow continuously.[11] 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: 0.0.2-3.30.0.2.3 These remaining teeth are peg-like and rootless and are of unique composition.[25] The teeth consist of 14 upper and 12 lower jaw molars.[6] The nasal area of the aardvark is another unique area, as it contains ten nasal conchae, more than any other placental mammal.[16]

The sides of the nostrils are thick with hair.[22] The tip of the snout is highly mobile and is moved by modified mimetic muscles.[16] The fleshy dividing tissue between its nostrils probably has sensory functions,[5] but it is uncertain whether they are olfactory or vibratory in nature.[26] Its nose is made up of more turbinate bones than any other mammal, with between 9 and 11, compared to dogs with 4 to 5.[11] With a large quantity of turbinate bones, the aardvark has more space for the moist epithelium, which is the location of the olfactory bulb.[11] The nose contains nine olfactory bulbs, more than any other mammal.[22] Its keen sense of smell is not just from the quantity of bulbs in the nose but also in the development of the brain, as its olfactory lobe is very developed.[13] The snout resembles an elongated pig snout. The mouth is small and tubular, typical of species that feed on ants and termites. The aardvark has a long, thin, snakelike, protruding tongue (as much as 30 centimetres (12 in) long)[6] and elaborate structures supporting a keen sense of smell.[27] The ears, which are very effective,[6] are disproportionately long, about 20–25 centimetres (7.9–9.8 in) long.[22] The eyes are small for its head, and consist only of rods.[22]

Digestive system

The aardvark's stomach has a muscular pyloric area that acts as a gizzard to grind swallowed food up, thereby rendering chewing unnecessary.[5] Its cecum is large.[16] Both sexes emit a strong smelling secretion from an anal gland.[5] Its salivary glands are highly developed and almost completely ring the neck;[16] their output is what causes the tongue to maintain its tackiness.[22] The female has two pairs of teats in the inguinal region.[16]

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.[28]

Habitat and range

Aardvarks are found in sub-Saharan Africa, where suitable habitat (savannas, grasslands, woodlands and bushland) and food (i.e., ants and termites) is available.[12] They spend the daylight hours in dark burrows to avoid the heat of the day.[29] The only major habitat that they are not present in is swamp forest, as the high water table precludes digging to a sufficient depth.[1] They also avoid terrain rocky enough to cause problems with digging.[30] They have been documented as high as 3,200 metres (10,500 ft) in Ethiopia. They are present throughout sub-Saharan Africa all the way to South Africa with few exceptions including the coastal areas of Namibia, Ivory Coast, and Ghana. They are not found in Madagascar.[1]

Ecology and behaviour

Aardvark resting
Entrance to a burrow
Emerging from a burrow

Aardvarks live for up to 23 years in captivity.[16] Its keen hearing warns it of predators: lions, leopards, cheetahs, African wild dogs, hyenas, and pythons.[6][26] Some humans also hunt aardvarks for meat.[6] Aardvarks can dig fast or run in zigzag fashion to elude enemies, but if all else fails, they will strike with their claws, tail and shoulders, sometimes flipping onto their backs lying motionless except to lash out with all four feet.[26] They are capable of causing substantial damage to unprotected areas of an attacker.[11] They will also dig to escape as they can. Sometimes, when pressed, aardvarks can dig extremely quickly. [26]

Feeding

The aardvark is nocturnal and is a solitary creature that feeds almost exclusively on ants and termites (myrmecophagy);[5] the only fruit eaten by aardvarks is the aardvark cucumber.[26] In fact, the cucumber and the aardvark have a symbiotic relationship as they eat the subterranean fruit, then defecate the seeds near their burrows, which then grow rapidly due to the loose soil and fertile nature of the area. The time spent in the intestine of the aardvark helps the fertility of the seed, and the fruit provides needed moisture for the aardvark.[11][26] They avoid eating the African driver ant and red ants.[31] Due to their stringent diet requirements, they require a large range to survive.[30] An aardvark emerges from its burrow in the late afternoon or shortly after sunset, and forages over a considerable home range encompassing 10 to 30 kilometres (6.2 to 18.6 mi). While foraging for food, the aardvark will keep its nose to the ground and its ears pointed forward, which indicates that both smell and hearing are involved in the search for food. They zig-zag as they forage and will usually not repeat a route for 5–8 days as they appear to allow time for the termite nests to recover before feeding on it again.[31]

During a foraging period, they will stop to dig a "V" shaped trench with their forefeet and then sniff it profusely as a means to explore their location.[5] When a concentration of ants or termites is detected, the aardvark digs into it with its powerful front legs, keeping its long ears upright to listen for predators, and takes up an astonishing number of insects with its long, sticky tongue—as many as 50,000 in one night have been recorded. Its claws enable it to dig through the extremely hard crust of a termite or ant mound quickly. It avoids inhaling the dust by sealing the nostrils.[29] When successful, the aardvark's long (up to 30 centimetres (12 in))[2] tongue licks up the insects; the termites' biting, or the ants' stinging attacks are rendered futile by the tough skin. After an aardvark visit at a termite mound, other animals will visit to pick up all the leftovers.[32] Termite mounds alone do not provide enough food for the aardvark, so they look for termites that are on the move. When these insects move, they can form columns 10–40 metres (33–131 ft) long and these tend to provide easy pickings with little effort exerted by the aardvark. These columns are more common in areas of livestock or other hoofed animals.[32] The trampled grass and dung attract termites from the Odontotermes, Microtermes, and Pseudacanthotermes genera.[32]

On a nightly basis they tend to be more active during the first portion of night (roughly the four hours between 8:00 p.m. and 12:00 a.m.); however, they do not seem to prefer bright or dark nights over the other. During adverse weather or if disturbed they will retreat to their burrow systems. They cover between 2 and 5 kilometres (1.2 and 3.1 mi) per night; however, some studies have shown that they may traverse as far as 30 kilometres (19 mi) in a night.[5]

Aardvarks shift their circadian rhythms to more diurnal activity patterns in response to a reduced food supply. This survival tactic may signify an increased risk of imminent mortality.[33]

Vocalization

The aardvark is a rather quiet animal. However, it does make soft grunting sounds as it forages and loud grunts as it makes for its tunnel entrance.[30] It makes a bleating sound if frightened.[31] When it is threatened it will make for one of its burrows. If one is not close it will dig a new one rapidly. This new one will be short and require the aardvark to back out when the coast is clear.[31]

Movement

The aardvark is known to be a good swimmer and has been witnessed successfully swimming in strong currents.[31] It can dig a yard of tunnel in about five minutes,[30] but otherwise moves fairly slowly.

When leaving the burrow at night, they pause at the entrance for about ten minutes, sniffing and listening. After this period of watchfulness, it will bound out and within seconds it will be 10 metres (33 ft) away. It will then pause, prick its ears, twisting its head to listen, then jump and move off to start foraging.[30]

Aside from digging out ants and termites, the aardvark also excavates burrows in which to live, which generally fall into one of three categories: burrows made while foraging, refuge and resting location, and permanent homes.[5] Temporary sites are scattered around the home range and are used as refuges, while the main burrow is also used for breeding. Main burrows can be deep and extensive, have several entrances and can be as long as 13 metres (43 ft).[5] These burrows can be large enough for a person to enter.[6] The aardvark changes the layout of its home burrow regularly, and periodically moves on and makes a new one. The old burrows are an important part of the African wildlife scene. As they are vacated, then they are inhabited by smaller animals like the African wild dog, ant-eating chat, Nycteris thebaica and warthogs.[31] Other animals that use them are hares, mongooses, hyenas, owls, pythons, and lizards. Without these refuges many animals would die during wildfire season.[31] Only mothers and young share burrows; however, the aardvark is known to live in small family groups or as a solitary creature.[6] If attacked in the tunnel, it will escape by digging out of the tunnel thereby placing the fresh fill between it and its predator, or if it decides to fight it will roll onto its back, and attack with its claws.[6] The aardvark has been known to sleep in a recently excavated ant nest, which also serves as protection from its predators.[34]

Reproduction

Aardvark mother and young

Aardvarks pair only during the breeding season; after a gestation period of seven months,[5] one cub weighing around 1.7–1.9 kilograms (3.7–4.2 lb)[16] is born during May–July.[6] When born, the young has flaccid ears and many wrinkles. When nursing, it will nurse off each teat in succession.[26] After two weeks, the folds of skin disappear and after three, the ears can be held upright.[26] After 5–6 weeks, body hair starts growing.[26] It is able to leave the burrow to accompany its mother after only two weeks and eats termites at 9 weeks,[26] and is weaned between three months[16] and 16 weeks.[5] At six months of age, it is able to dig its own burrows, but it will often remain with the mother until the next mating season,[5] and is sexually mature from approximately two years of age.[16]

Conservation

Aardvarks were thought to have declining numbers,[6] however, this is possibly because they are not readily seen.[1] There are no definitive counts because of their nocturnal and secretive habits; however, their numbers seem to be stable overall. They are not considered common anywhere in Africa, but due to their large range, they maintain sufficient numbers. There may be a slight decrease in numbers in eastern, northern, and western Africa. Southern African numbers are not decreasing. It has received an official designation from the IUCN as least concern.[1] However, they are a species in a precarious situation, as they are so dependent on such specific food; therefore if a problem arises with the abundance of termites, the species as a whole would be affected drastically.[5]

Recent research suggests that aardvarks may be particularly vulnerable to alterations in temperature caused by climate change. Droughts negatively impact the availability of termites and ants, which comprise the bulk of an aardvark's diet.[35] Nocturnal species faced with resource scarcity may increase their diurnal activity to spare the energy costs of staying warm at night, but this comes at the cost of withstanding high temperatures during the day. A study on aardvarks in the Kalahari Desert saw that five out of six aardvarks being studied perished following a drought.[36] Aardvarks that survive droughts can take long periods of time to regain health and optimal thermoregulatory physiology, reducing the reproductive potential of the species.

Aardvarks handle captivity well. The first zoo to have one was London Zoo in 1869, which had an animal from South Africa.[26]

Mythology and popular culture

F-111 Aardvark
F-14 Tomcat from VF-114 Aardvarks with the squadron mascot painted on the tail

In African folklore, the aardvark is much admired because of its diligent quest for food and its fearless response to soldier ants. Hausa magicians make a charm from the heart, skin, forehead, and nails of the aardvark, which they then proceed to pound together with the root of a certain tree. Wrapped in a piece of skin and worn on the chest, the charm is said to give the owner the ability to pass through walls or roofs at night. The charm is said to be used by burglars and those seeking to visit young girls without their parents' permission.[37] Also, some tribes, such as the Margbetu, Ayanda, and Logo,[5] will use aardvark teeth to make bracelets, which are regarded as good luck charms.[6] The meat, which has a resemblance to pork, is eaten in certain cultures.[5]

The ancient Egyptian god Set is usually depicted with the head of an unidentified animal, whose similarity to an aardvark has been noted in scholarship.[38]

The titular character and his families from Arthur, an animated television series for children based on a book series and produced by WGBH, shown in more than 180 countries, is an aardvark.[39] In the first book of the series, Arthur's Nose (1976), he has a long, aardvark-like nose,[40] but in later books, his face becomes more rounded.[41]

Otis the Aardvark was a puppet character used on Children's BBC programming.

An aardvark features as the antagonist in the cartoon The Ant and the Aardvark as well as in the Canadian animated series The Raccoons.

The supersonic fighter-bomber F-111/FB-111 was nicknamed the Aardvark because of its long nose resembling the animal. It also had similarities with its nocturnal missions flown at a very low level employing ordnance that could penetrate deep into the ground. In the US Navy, the squadron VF-114 was nicknamed the Aardvarks, flying F-4s and then F-14s. The squadron mascot was adapted from the animal in the comic strip B.C., which the F-4 was said to resemble.

Cerebus the Aardvark is a 300-issue comic book series by Dave Sim.

Footnotes

  1. ^ a b c d e Taylor, A.; Lehmann, T. (2015). "Orycteropus afer". IUCN Red List of Threatened Species. 2015: e.T41504A21286437. doi:10.2305/IUCN.UK.2015-2.RLTS.T41504A21286437.en. Retrieved 12 November 2021.
  2. ^ a b Hoiberg 2010, pp. 3–4
  3. ^ "Aardvark, n." Dictionary of South African English. Dictionary Unit for South African English, 2018. 26 February 2019.
  4. ^ a b Schlitter 2005, p. 86
  5. ^ a b c d e f g h i j k l m n o p q van Aarde 1984, pp. 466–467
  6. ^ a b c d e f g h i j k l m n Goodwin 1997, pp. 2–3
  7. ^ Merriam-Webster Online Dictionary 2010
  8. ^ "aardvark, n." OED Online, Oxford University Press, March 2018, www.oed.com/view/Entry/22. Accessed 24 May 2018.
  9. ^ "Aardvark, n." Dictionary of South African English. Dictionary Unit for South African English, 2018. 25 February 2019.
  10. ^ a b Shoshani 2002, p. 618
  11. ^ a b c d e f Shoshani 2002, p. 619
  12. ^ a b African Wildlife Foundation 2013
  13. ^ a b c d e f g h Rahm 1990, pp. 453–454
  14. ^ Asher, Bennett & Lehmann 2009, p. 854
  15. ^ Rodriguez 2013, p. 6
  16. ^ a b c d e f g h i j k l m Rahm 1990, pp. 450–451
  17. ^ Shoshani 2002, p. 620
  18. ^ Cote S, Werdelin L, Seiffert ER, Barry JC (March 2007). "Additional material of the enigmatic Early Miocene mammal Kelba and its relationship to the order Ptolemaiida". Proc Natl Acad Sci USA. 104 (13): 5510–5. Bibcode:2007PNAS..104.5510C. doi:10.1073/pnas.0700441104. PMC 1838468. PMID 17372202.
  19. ^ Seiffert, Erik R (2007). "A new estimate of afrotherian phylogeny based on simultaneous analysis of genomic, morphological, and fossil evidence". BMC Evolutionary Biology. 7 (1): 224. doi:10.1186/1471-2148-7-224. PMC 2248600. PMID 17999766.
  20. ^ Buckley, Michael (2013). "A Molecular Phylogeny of Plesiorycteropus Reassigns the Extinct Mammalian Order 'Bibymalagasia'". PLOS ONE. 8 (3): e59614. Bibcode:2013PLoSO...859614B. doi:10.1371/journal.pone.0059614. PMC 3608660. PMID 23555726.
  21. ^ Chisholm, Hugh, ed. (1911). "Aard-vark" . Encyclopædia Britannica. Vol. 1 (11th ed.). Cambridge University Press. p. 2.
  22. ^ a b c d e f g h i j Rahm 1990, p. 452
  23. ^ Legendre, Lucas J.; Botha-Brink, Jennifer (11 July 2018). "Digging the compromise: investigating the link between limb bone histology and fossoriality in the aardvark (Orycteropus afer)". PeerJ. 6: e5216. doi:10.7717/peerj.5216. PMC 6045922. PMID 30018860.
  24. ^ Haussmann, Natalie S.; Louw, Michelle A.; Lewis, Simone; Nicol, Keegan J. H.; van der Merwe, Stephni; le Roux, Peter C. (1 August 2018). "Ecosystem engineering through aardvark (Orycteropus afer) burrowing: Mechanisms and effects". Ecological Engineering. 118: 66–72. doi:10.1016/j.ecoleng.2018.04.022. hdl:2263/65084. S2CID 104179393.
  25. ^ Martin 1983, p. 377
  26. ^ a b c d e f g h i j k Rahm 1990, p. 458
  27. ^ Taylor & Skinner 2004, p. 106
  28. ^ Anon 2003
  29. ^ a b Anon 2013
  30. ^ a b c d e Rahm 1990, p. 455
  31. ^ a b c d e f g Rahm 1990, p. 456
  32. ^ a b c Rahm 1990, p. 457
  33. ^ Weyer, Nora Marie; Fuller, Andrea; Haw, Anna Jean; Meyer, Leith Carl Rodney; Mitchell, Duncan; Picker, Mike; Rey, Benjamin; Hetem, Robyn Sheila (2020). "Increased Diurnal Activity Is Indicative of Energy Deficit in a Nocturnal Mammal, the Aardvark". Frontiers in Physiology. 11: 637. doi:10.3389/fphys.2020.00637. ISSN 1664-042X. PMC 7358442. PMID 32733261.
  34. ^ Anon 2013a
  35. ^ Melton, Derek A. (June 1976). "The biology of aardvark (Tubulidentata-Orycteropodidae)". Mammal Review. 6 (2): 75–88. doi:10.1111/j.1365-2907.1976.tb00204.x. ISSN 0305-1838.
  36. ^ Rey, Benjamin; Fuller, Andrea; Mitchell, Duncan; Meyer, Leith C. R.; Hetem, Robyn S. (31 July 2017). "Drought-induced starvation of aardvarks in the Kalahari: an indirect effect of climate change". Biology Letters. 13 (7): 20170301. doi:10.1098/rsbl.2017.0301. PMC 5543026. PMID 28724691.
  37. ^ Rebecca 2007
  38. ^ te Velde 1997, p. 13
  39. ^ WGBH 2013
  40. ^ Arthur's Nose, Thriftbooks; accessed 2020.09.29.
  41. ^ Arthur's Eyes, Thriftbooks; accesses 2020.09.29.

References

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Aardvark: Brief Summary

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Skeleton of an aardvark

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 most other insectivores, it has a long snout, similar to that of a pig, which is used to sniff out food.

The aardvark is found over much 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. The animal is listed as "least concern" by the IUCN, although its numbers are decreasing. Aardvarks are afrotheres, a clade which also includes elephants, manatees, and hyraxes.

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