AARDVARK: CHARACTERISTICS, HABITAT, FEEDING, REPRODUCTION - BIOLOGY - 2024

The aardvark, aaedak or aardvark (Orycteropus afer) is a placental mammal that is part of the Orycteropodidae family. Its body has very particular characteristics, such as a long snout, at the highly mobile end of which are the nostrils.

In addition, its long ears, similar to those of a rabbit, stand out. Its tongue is long and protractile, and can protrude from the mouth up to 30 centimeters. The saliva that covers it is sticky and dense. This allows termites and ants, their main food, to adhere to it, to be later taken to the mouth and swallowed whole.

Aardvark. Source: MontageMan

The Orycteropus afer is found in various regions of sub-Saharan Africa. However, there are several areas where it is absent. These include the coast of Namibia, Ghana, the Ivory Coast, and the Namib and Sahara deserts.

The anteater was previously associated with the anteater and Old World pangolins. However, after various investigations based on DNA, experts group the aardvark into a different order, the Tubulidentata, of which it is the only representative.

characteristics

Size

The aardvark weighs around 60 to 80 kilograms. Regarding the length of the body, it measures between 105 and 130 centimeters, with a tail that reaches 70 centimeters. The height at the shoulder is 60 centimeters and the circumference is approximately 100 centimeters.

Fur

The hair is thin and short on the head, tail and neck. However, on the rest of the body it is darker and longer, especially on the legs. The nostrils are surrounded by dense hair, which helps filter dust and dirt, which it lifts with its paws as it digs into the ground.

In this species, the skin performs a protective function, mainly due to its hardness. A peculiarity of the coat is that in adults it can become scarce, but in juveniles it is clearly appreciated.

Regarding the coloration, it is pale yellowish gray, with some spots of a reddish brown tone. In females, the tail area and sides of the face are lighter, while in males they are darker.

Extremities

When it walks, it is digitigrade, since it does so by supporting only the toes of the legs, without settling the plant. As for the limbs, they are muscular, the rear ones being longer than the front ones. These have lost the thumb, so they have four fingers, while the rear ones have five.

Each of the fingers end in a large, flattened, shovel-shaped claw. They use them to dig, in search of their food or to build their nest.

Teeth

The aardvark's teeth lack enamel and consist of premolars and molars, shaped like pegs. At birth, the calf has canines and incisors, which later fall off and are not replaced.

Replacing the pulp cavity, each tooth has a group of thin, vertical tubes, composed of vasodentin, a type of dentin. These tubules are joined by dental cement.

As for the number of columns, they will depend on the size of the tooth. Thus, the largest tooth has about 1500 of these structures.

Head

The head is elongated and is supported by a thick and short neck. The end of the muzzle is mobile and has a disk, where the nostrils meet. In relation to the mouth, it is tubular and small. The tongue is thin and long, being able to protrude from the muzzle up to 30 centimeters.

Among its most outstanding characteristics are the ears. These are long and tubular, similar to that of the rabbit. They can keep them upright or fold them, thus preventing dust from getting in, as they dig into the ground.

Nose

The aaedak's nose is made up of approximately 10 nasal shells, many more than other mammals. Thanks to this large number of nasal turbinate bones, this species has more space for the nine olfactory bulbs it has.

The Orycteropus afer has an acute ability to perceive odors. This is not only due to the large number of olfactory bulbs. Also influences the great development of the olfactory lobe, which is found in the brain. In the following video you can see an aardvark in nature:

Digestive system

The aardvark's stomach has a muscular pyloric area, which is responsible for grinding the food it has eaten. Because of this, said animal does not chew its food. The salivary glands are large, reaching almost to the neck area. The saliva that is secreted is sticky and of a high density.

The burrow, an ecological benefit

The aardvark digs different types of burrows: feeding, shallow and temporary, which serve to hide from predators and residential. The latter are the largest and have a complex structure, because there the animal takes shelter during the day and the mother also lives with her young for a long time.

In the main burrow, the aaedak can share space with species other than its own. Research on this residential shelter shows that, compared to the surrounding soil, the internal terrain is more humid and is 4-18 degrees Celsius cooler, depending on the time of day.

These differences hold true for both newly built and older shelters. For this reason, experts have designated Orycteropus afer as the ecological engineer.

Importance

The burrows that aardvarks build in grasslands are of great ecological importance. These refuges create a microhabitat, which favors the development of other vertebrate and invertebrate species.

According to observations made by experts, about 39 species of animals live in the burrow. These include small mammals, reptiles, birds, and amphibians. They often use it as a short- or long-term refuge and as an area to care for their young.

Within the group of birds is the blue swallow (Hirundo atrocaerulea). This is seriously threatened with extinction, in the southern region of Africa. Their survival as a species depends largely on the Orycteropus afer, as the bird builds its nest within the mammal's burrow.

On the other hand, the refuges that the aaedak have abandoned are inhabited by smaller animals, such as hares, African wild dogs, lizards and hyenas. Without these shelters, many of these species would die during the dry season, where they protect themselves from high temperatures and numerous forest fires.

Taxonomy and subspecies

Previously, the Orycteropus afer was cataloged within the same genus of the South American anteater (Myrmecophaga). However, it was later grouped into its own genus (Orycteropus) and, from 1872, into the order Tubulidentata.

This order was long related to the Pholidotas and the Xenarthrans. However, the 20th century set a new standard in the classification of aaedak.

After various investigations, seven species were merged into one, Orycteropus afer. Furthermore, since then, the order Tubulidentata groups together a single living species, the aardvark.

Recently, phylogenetic analyzes integrated aardvark into the superorder Afrotheria, together with the orders Afrosoricida (tenrecs and golden mole) and Macroscelidea (elephant shrew).

-Taxonomic classification

-Animal Kingdom.

-Subreino: Bilateria.

-Filum: Cordate.

-Subfilum: Vertebrate.

-Superclass: Tetrapoda

-Class: Mammal.

-Subclass: Theria.

-Infraclass: Eutheria.

-Order: Tubulidentata.

-Family: Orycteropodidae.

-Gender: Orycteropus.

-Species: Orycteropus afer.

Subspecies:

Habitat and distribution

Distribution

In times past, the aaedak lived in Asia and Europe, but today it is distributed throughout much of sub-Saharan Africa. Thus, it is widespread in Zimbabwe, Botswana, Mozambique, Ethiopia, Senegal and South Africa. In addition, it is located in the Congo basin, although the habitat in the rain forests of West Africa is very little known.

Within the wide African geographic range where this species is present there are some exceptions. Such is the case of the Ivory Coast, the coastal zone of Namibia, Ghana and the Sahara Desert and Namib.

Habitat

The habitat of the Orycteropus afer is determined mainly by the existence of soils suitable for burrowing and by the abundance of its favorite prey: termites and ants.

In relation to the geographical height, it can be distributed up to 3,200 meters above sea level, as in Ethiopia. However, it is rare on steep slopes.

This African species lives in almost all types of ecosystems, except in deserts and marshes. Usually avoid areas with compact, rocky terrain or that are frequently flooded.

In this sense, it is not present in swampy forests, because the high water table prevents it from digging to the depth it requires for its burrow. Likewise, the very rocky terrain prevents excavation.

On the other hand, it tends to occupy farmland, as in the Drakensberg Midlands, and various human-disturbed areas, such as the Natal Midlands, both areas located in KwaZulu-Natal.

It can often live in temporary holes, which are a few meters long. However, they generally reside in intricate and complex burrows. These have more than eight entrances and extend up to twenty feet below the ground.

The location of the main shelter may be different from the feeding area, so at night you usually walk between the two sites. The burrow is used during the day as a resting place, although it is also used to escape the stalking of predators. In this video you can see an aardvark in its habitat:

State of conservation

The aardvark has a very widespread habitat, however, its population has been exterminated in many areas, especially in agricultural ones. In this way, it is vulnerable in those areas with high concentrations of people.

The IUCN lists Orycteropus afer as a species with a lower risk of extinction. However, due to the fact that its diet depends almost exclusively on terns and ants, it can be seriously threatened if there is any variation in the availability of these insects.

- Threats

Agricultural expansion

Today, the aaedak has lost much of its natural habitat due to land use for agricultural practices, especially on farmland. This has motivated the aardvark to live in fields and in areas where there are breeding animals, causing problems mainly related to their burrows.

These shelters are large and deep, thus destabilizing the terrain. When cattle transit the area, they fall into the hole, which can have serious consequences for the animal. Also, burrows damage roads, turning roads into unstable terrain and unsafe to travel.

Hunting

For many years, this species has been hunted for trade for teeth, claws, and skin. These are used in the making of amulets, bracelets and in some traditional medicines.

Another product extracted from the aardvark is its meat. This is consumed locally or is sold illegally in regional markets. Despite being a legally restricted activity, it is carried out in some countries such as Mozambique and Zambia.

Climate change

Climate change severely affects environmental conditions. Thus, the temperature and the drought and rain cycles alter, moving away from the patterns that characterize each region.

The Orycteropus afer is seriously affected by the desiccation of its habitat. In 2013, a large number of anteaters were killed in the Tswalu Kalahari Reserve. These deaths were attributed to the abnormal periods of drought and heat in the area that occurred that year.

Studies reveal that the dead animals were extremely thin, presumably the product of poor diet. In this sense, environmental conditions influenced the decrease in termite and ant populations.

Interestingly, as a result of climate change, these aardvarks also changed their habits, becoming more diurnal. Thus, they fed in the morning and afternoon, instead of exclusively at night. This same situation also occurred in Namibia, starting in 1980, and in some areas of Limpopo.

- Conservation actions

Various strategies are being implemented by the governments of the countries where Orycteropus afer lives. One of these is the placement of tires on the fences of agricultural plantations. Thus, the aardvark passes through these, using them as passageways.

There are also education and awareness campaigns, aimed at ranchers and farmers. In these, the recommendations aimed at reducing the damage that the aardvark could cause both in plantations, as well as in infrastructure and in breeding animals are highlighted.

In addition, in South Africa various national reserves have been created, where the species is protected. These include Mokala National Park, Welgevonden Game Reserve, and Pilanesberg National Park.

Feeding

- Diet

The aaedak is myrmecophagus, since its diet specializes in termites and ants. However, it may occasionally feed on beetle pupae.

It can eat almost any variety of ants that are present in the area. However, some of the preferred species are Anoplolepis custodiens and Trinervitermes trinervoides. As for termites, some of the genera consumed by aaedak are Odontotermes, Pseudacanthotermes and Microtermes.

To get the water, you usually do it through your food, like cucumber. This is almost the only fruit you eat, from which you get a high percentage of the fluid your body requires.

Furthermore, the animal acts as a dispersal agent for the plant species. When it defecates, it expels the seeds, which grow rapidly in the fertile soil surrounding the burrow.

- Food method

Location of the dams

In the late afternoon or shortly after sunset, the aardvark leaves its shelter in search of its food. Many times, to find ant nests, the animal travels long distances, since its home range covers between 10 and 30 kilometers.

In a particular way, this species does not travel the same route that it has traveled, but after 5 to 8 days have passed. This behavior could be associated with the time it takes for the nest to form again.

While looking for food, the aaedak keeps its nose on the ground and its ears forward. In this way, it tries to locate its prey, by the smell they have.

Upon detecting a concentration of termites or ants, the Orycteropus afer quickly burrows into the ground or in the bark of trees, using its strong and powerful forelegs.

At the same time, it keeps its ears upright, to be aware of the presence of a predator. Also, it seals the nostrils, thus preventing the entry of dust.

Capture

Once it has access to the nest, it inserts its long protractile tongue, which projects up to 30 centimeters outside the mouth. In addition, because it is covered with a thick and sticky saliva, the insects remain attached and are carried to the mouth. In one night, this African mammal can capture up to 50,000 insects.

The food is then swallowed without chewing and, once in the stomach, digestion occurs in the pyloric region of this muscular organ.

During the process of capturing food, ants or termites can bite the aaedak on the legs. These attacks do not cause injury to the animal, due to the protection offered by the thick skin that covers its entire body.

Termite mounds often do not provide enough food, so the animal is forced to search for termites outside the nest. When these insects move, they usually form columns several meters long. This makes it easier for the aardvark to catch it, since it only runs its tongue over these and ingests them.

Reproduction

Orycteropus afer sexually matures between two and three years of age. The external scent glands of the male are located at the base of the foreskin of the penis. These secrete a musk, which is part of the mating process. Also, both sexes have scent glands on the hips and elbows.

In relation to the reproductive system, the female has ovaries, uterus, and vagina. For its part, the male has a penis and testicles, which are internally, at the level of the inguinal canal. These can move to a subcutaneous position. As for the accessory sex glands, it has a prostate, seminal vesicles and bulbourethral glands.

Generally, the gestation period lasts seven months. The birth of the young varies according to the geographical location. Thus, those who live in North Africa, the young are born between October and November, while those who live in South Africa, the delivery occurs between the months of May to July. In this video you can see the mating of two specimens:

The babies

The young are born inside the burrow, where they remain for several weeks. The skin is furred and has many folds, which disappear after the second week. As for the ears, they are flaccid, being able to keep them erect after the third week.

In relation to its weight, the newborn has a body mass of approximately 1.7 to 1.9 kilograms. When the youngster is two weeks old, he comes out of the burrow, thus exploring, together with his mother, the environment that surrounds him. Between the fifth and sixth week, body hair begins to grow.

At nine weeks, the young can already hunt ends, although it continues to be breastfed by the mother until three months. The calf becomes independent of the mother at six months of age, when it can dig its burrow. However, some may remain with their mother until the next breeding season.

Behavior

The aardvark is solitary and only forms a pair during mating. It is a nocturnal animal, however, it often leaves its burrow during the day to sunbathe.

When it comes out of the burrow, the aaedak does a kind of ritual. Thus, he stands at the entrance, remaining motionless for several minutes. Then it moves forward, hopping and looking around, looking for possible predators. Finally, if it does not see any threat, it begins to move across the terrain at a slow trot, in search of its food.

When they sleep, it cuddles their body, forming a kind of tight ball. In addition, it blocks the entrance to the burrow, leaving only a small opening at the top.

This species has poor vision, however, it has an excellent sense of hearing. Their ears are long and can move independently, to more efficiently pick up sound waves. Also, they can be folded back and closed, thus preventing the entry of dust, while digging in the ground.

In relation to smell, it is highly developed. Your nose has specialized structures that increase the catchment surface for olfactory signals.

When the aaedak feels threatened, they can quickly dig a shelter or run in a zigzag, while vocalizing bleats and growls. If the predator does not move away, it strikes it with its powerful claws and its tail. Their attacks can cause serious damage to vulnerable areas on the animal's body.

References

1. Ratzloff, E. (2011). Orycteropus afer. Animal Diversity Web. Recovered from animaldiversity.org.
2. Wikipedia (2019). Aardvark. Recovered from en.wikipedia.org.
3. Taylor, A., Lehmann, T. (2015). Orycteropus afer. The IUCN Red List of Threatened Species 2015. Recovered from iucnredlist.org.
4. Bathabile Ndlovu (2017). Orycteropus afer. Recovered from sanbi.org.
5. Tree of Life Web Project. (2000). aardvarks, ant bears. Recovered from tolweb.org.
6. ITIS (2019). Orycteropus afer. Recovered from itis.gov.
7. Laura Klappenbach (2019). Aardvark Fast Facts. Recovered from thoughtco.com.
8. A.Taylor, PALindsey, JDSkinner (2001). The feeding ecology of the aardvark Orycteropus afer. Recovered from sciencedirect.com.
9. John Wible (2018). A is for Aardvark. Recovered from carnegiemnh.org.
10. Taylor A, Cilliers S, Meyer L, Wilson AL. 2016. A conservation assessment of Orycteropus afer. Recovered from ewt.org.za.
11. Wojick KB, Langan JN, Terio KA, Righton A, Drees R. (2018). Anatomy, histology, and diagnostic imaging of the reproductive tract of male aardvark (Orycteropus afer). Recovered from ncbi.nlm.nih.gov.
12. Melton, Derek (2008). The biology of Aardvark (Tubulidentata-Orycteropodidae). Recovered from researchgate.net.