ARMADILLOS: CHARACTERISTICS, MORPHOLOGY, FEEDING, HABITAT - BIOLOGY - 2025

The armadillos or dasypodid are mammals belonging to the Cingulata order, which are characterized by a hard armor, like a shell. This shell is made up of bone plates, which can form between 6 and 11 mobile bands, being covered by a keratinous tissue.

The oldest fossil is that of Dasypus bellus, which lived in North and South America between 2.5 and 11 million years ago. Its size was larger than that of the current armadillo, about 2.5 times larger, and its armor was more robust.

Source: pixabay.com

With their long claws they dig burrows on the banks of streams or in dry trees. When threatened, armadillos run to the shelter, and if they can't get one, they curl up to protect their lower body, which is not protected.

These animals have a low body temperature, between 32.7 and 35.5 ºC, lower than the rest of mammals. In addition to this, the armor that covers almost their entire body makes it difficult for them to regulate their internal temperature.

Relationship with science

The species known as the long-nosed armadillo (Dasypus hybridus) is the only natural host for the bacterium Mycobacterium leprae, the transmitting agent of leprosy, an infectious disease that affects several organs, especially the peripheral nervous system.

This animal is used, within the field of science, as a model to study this serious condition. As a result of these investigations, the Venezuelan doctor and researcher Dr. Jacinto Convit developed a vaccine that prevents and cures leprosy, this terrible disease that in past times afflicted many people.

In 1989 in Brazil, the Leishmania parasite was isolated in a group of armadillos of the species Dasypus novemcinctus (black tatú) that were under study. Clinically, lesihmaniasis is a condition that ranges from skin ulcers to severe inflammation of the spleen and liver.

The armadillo is a reservoir for this infectious agent, which is why it is used in research centers to advance knowledge about the disease.

General characteristics

Size and color

Armadillos can vary in size and color. The pink fairy armadillo (Chlamyphorus truncatus) measures approximately 10 to 14 centimeters, weighing about 85 grams.

The largest species is the giant dark brown armadillo (Priodontes maximus), reaching 150 centimeters, weighing up to 54 kilograms. Animals can be found in various shades of yellow, black, gray or reddish.

Armor

This carapace is made up of several plates of bone covered by epidermal scales called scutes. Extra armor covers the head on top and the tops of the legs and tail. The lower surface of the body has smooth, furry skin.

Between the plates there are bands, composed of a more flexible tissue that allows the movement of the animal.

Senses

They have a long and particularly sticky tongue, which they use to capture prey such as ants and termites. Her nose is pointed and long. The sense of smell is highly developed, being able to locate insects that are up to 20 centimeters below the ground in the area.

Sight is poorly developed, so hearing is used to detect the presence of predators. The ears are large and oval in shape, covered with small plates with an irregular distribution.

Reproductive organs

Males have two testicles, located inside the abdominal cavity, and a prominent, retractable penis. Armadillo females have a urogenital groove, an external clitoris, and ovaries, which are located in the pelvis. They generally have pectoral breasts.

This group of mammals has sexual dimorphism, since the male is usually larger than the female.

Taxonomy

Animalia Kingdom. Edge: Chordata. Class: Mammalia. Infraclass: Placentalia. Superorder: Xenarthra. Order: Cingulata. Family: Dasypodidae.

Sub family Dasypodinae

They have armor that lacks capillary coverage, which makes armadillos very sensitive to variations in weather. For this reason they are more active at night, when there are no high temperatures that could raise the internal temperature of your body. Representative: Southern long-nosed armadillo.

-Genus Dasypus.

Sub family Euphractinae

A characteristic of this group is the abundance of hair that they have on the body, with a preponderance in the lower part. The bones of the female's skull are longer, compared to the rest of the Dyasiponidae family. This confirms the sexual dimorphism present in this group. Representative: Pichiciego mayor.

-Generas: Calyptophractus, Chaetophractus, Chlamyphorus, Euphractus, Zaedyus.

Sub family Tolypeutinae

Adult limbs weigh approximately 1 to 1.5 kilos, measuring around 12 to 18 inches. Their armor is made up of ossified plates, connected by flexible bands. This shell covers the side and back of its body, the head, tail, ear and outside of the legs.

In addition, the armor creates a layer of air between the cover and the body, isolating the body of the animal. This is favorable for their survival in arid climates. Their diet is based on termites, mollusks, fruits and carrion. Representatives: Tatú bolita and three-banded armadillo.

-Genera: Cabassous. Priodonts, Tolypeutes.

Morphology

Shell

Its body has an external armor covered by dermal scales. This is divided into three regions: the bands of the back, the central region and the shield, located in the pelvis. In the central area, the plates are separated by a soft skin, allowing it to have mobility to move.

Osteoderms, which are the dermal projections that the shell has, have characteristics of each genus and species, being able to have rectangular or pentagonal shapes. Between the back plates, the armadillo has bristly hairs, being hairier in the belly area.

When the young are born, they are covered by a soft leathery skin that will later strengthen, to form the shell.

Legs

Its legs are short. The anterior ones have 4 fingers and the posterior ones have 5, all with sharp and strong claws, the middle ones being larger than the rest. These facilitate their behavior as animals with habits of digging in the ground or climbing trees and branches.

Head

Its skull is small and flattened or shovel-shaped, with a long jaw ending in a narrow snout. Their teeth grow continuously, they are small and cylindrical. They occur in number of up to 25 in each jaw. The salivary glands are large.

Skeleton

In some species, the cervical vertebrae 2, 3 and 4 are usually welded. The bones of the hind legs, tibia and fibula, fuse distally and proximally.

Glands

They have a modified sweat gland, called the odoriferous gland, located in the pelvis, on the back of the carapace. These secrete an oily and fetid substance, impregnating the lair in order to mark the territory.

They also have perianal glands, which secrete a liquid with an unpleasant odor in threatening situations.

Brain

The brain has a corpus callosum, which coordinates the function of the left and right brain hemispheres. It lacks a pineal gland, with Harder's gland being responsible for producing melatonin. The olfactory structures are highly developed.

Nose

The vomeronasal organ, an auxiliary structure for the sense of smell located between the nose and the mouth, is highly developed, measuring about 2 centimeters. The olfactory mucous membranes are very sensitive, which makes the sense of smell specialized.

Feeding

Armadillos are animals whose diet is based mainly on insects, however there are species that include a small percentage of plants, tubers or fruits in their diet. Some also eat eggs, mollusks, snails, and small amphibians.

They are nocturnal animals, and they put into practice some of their skills to find the foods in their diet. The armadillo can go without breathing underwater for up to six minutes, allowing it to dive and capture small mollusks.

As their front legs are well developed, they make it easy for them to climb trees, reach the highest branches and access nests to consume the eggs that are there. Thanks to its sharp claws, it can capture its prey, such as small birds and lizards.

The metabolism rate in these animals is low and they have a low body fat reserve, this means that much of the time they are active is spent looking for food. As the sense of sight is limited, they use their smell and hearing to find their prey.

Digestive system

Language

It is a long, thin and extensible muscle. In it are taste buds and mechanical.

Stomach

The armadillo's stomach has a single cavity that is lined with a glandular mucosa.

Bowels

The intestine can reach a total length of 5.7 times longer than the average body length of the armadillo.

Small intestine

It is formed by the duodenum, jejunum and ileum, whose muscular layer prevents the return of the contents from the large intestine.

Large intestine

The armadillo has no blind. Your large intestine has two sections that fulfill complementary functions within the digestive process.

• Colon: in these animals it is simple. It is made up of the ascending, transverse, and descending colon.
• Rectum: located in the lower part of the pelvic cavity, ending in the anal canal. The waste product of digestion is deposited in this section of the large intestine.

Liver

The lobes of the liver are separated by fissures, allowing it to slide past each other while the trunk extends and flexes.

Habitat

Its habitat is limited, considering that its body temperature is much lower than the rest of the mammals. For this reason, these species do not develop in desert or very cold regions, but in temperate climates.

This group is found on several continents, especially in South, Central and North America, extending from Argentina to Oklahoma, in North America.

They tend to live in wooded areas and bushes, being found to a greater extent in forests, since in the latter they easily get small invertebrates that are part of their diet.

It can function in the water, due to two mechanisms: it is able to hold its breath, allowing it to submerge, and if it needs to float in the river, it fills its lungs and intestines with air.

One of its favorite habitats is burrows, which it builds with its legs in the wet ground. Motivated by this, they will prefer a sandy type soil, which reduces body effort. If the earth has abundant wood debris, it could also serve as a source to capture ants and termites.

Circulatory system

Your circulatory system is made up of the heart, veins, and arteries, which make up a vascular network that enervates muscles and organs. The heart has 4 chambers: two ventricles and two atria.

The circulation is twofold, since it occurs in two cycles: major and minor. In the lesser circulation the blood leaves the heart to the lungs, where it is oxygenated. Upon returning to the heart, the blood is propelled to the rest of the body, which is known as major circulation.

Once every organ and tissue in the body takes nutrients and oxygen from the blood, it dumps its waste into it. This so-called "impure" blood reaches the heart, to start its oxygenation process again.

Armadillos conserve their energy through the miraculous network, made up of a system of veins and arteries, located mainly on the surface of their legs.

In this structure of the circulatory system, the warm blood carried by the arteries is cooled by coming into contact with the cold blood in the veins upstream. A few days of extreme cold can be deadly for armadillos, as they cannot raise their body temperature using this net.

Behavior

Defending

When threatened, armadillos may startle their prey by suddenly jumping more than a meter, then running and escaping. They can also hide in a burrow. Once inside, he arches his back, blocking the entrance with his shell and feet.

As it is an animal with skills as a digger, it can quickly bury itself in loose soil, camouflaging its body to avoid being seen by its attacker.

In the face of danger, some species, such as the three-banded armadillo, can protect themselves from the aggressor by rolling into a ball, retracting the head and hind legs, while contorting the frame.

They are rarely violent, but if a pregnant or nursing mother feels that her young are in danger, she becomes aggressive even towards her other young.

Reproductive

During the breeding season, armadillos have courtship behaviors towards the pair. These can be some touches between them in the dorsal area, movements of the tail or the elevation of this by the female, exposing her genitals, while the male smells her.

Despite being solitary, some pairs share the burrow during the mating season. However, in that season, adult males can sometimes be aggressive towards young males, being able to chase them.

References

1. Wikipedia (2018). Dasypus. Recovered from en.wikipedia.org.
2. Wikipedia (2018). Armadillo. Recovered from en.wikipedia.org.
3. Alfred L. Gardner (2018). Mammal Armadillo. Encyclopedia Britannica. Recovered from britannica.com.
4. New Word encyclopedia (2016). Armadillo. Recovered from newworldencyplopedia.org.
5. ITIS report (2018). Dasypodidae. Recovered from itis.gov.
6. Kahli McDonald, Julie Larson (2011). Dasypus novemcinctus. Animal diversity web. Recovered from animaldiversity.org.