The Armadillo

Dec 11, 2011 Features / Columnists, Interesting Creatures in Guyana

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Armadillos are placental mammals, known for having a leathery armor shell.
The word armadillo is Spanish for “little armored one”. The Aztec called them azotochtli, Nahuatl for “turtle-rabbit.”
There are approximately 10 extant genera and around 20 extant species of armadillo, some of which are distinguished by the number of bands on their armor. Their average length is about 75 centimetres (30 in), including tail; the giant armadillo grows up to 150 centimetres (59 in) and weighs up to 59 kilograms (130 lb), while the pink fairy armadillos are diminutive species with an overall length of 12 to 15 centimetres (five to six inches). All species are native to the Americas, where they inhabit a variety of environments.
Armadillos species are primarily found in South and Central America, particularly in
Paraguay and surrounding areas. Many species are endangered. Some species groups, such as the long-nosed armadillos, are widely distributed over the Americas, whereas others, such as the fairy armadillos, are concentrated in smaller ranges in South America.
One species, the nine-banded armadillo, (Dasypus novemcinctus), is found in the United States, primarily in the south central states (notably Texas), but with a range that extends as far east as South Carolina and Florida and as far north as Nebraska; they have been consistently expanding their range in North America over the last century due to a lack of natural predators, and have been found as far north as southern Illinois and Indiana.
Armadillos are prolific diggers with sharp claws. Many species use their sharp claws to dig for food, such as grubs, and to dig dens. The nine-banded armadillo prefers to build burrows in moist soil near the creeks, streams, and arroyos around which it lives and feeds. The diet of different armadillo species varies, but consists mainly of insects, grubs, and other invertebrates. Some species, however, feed almost entirely on ants and termites.
In common with other xenarthrans, armadillos in general have low body temperatures (33–36°C) and basal metabolic rates (from 40–60 per cent of that expected in a placental mammal of their mass). This is particularly true of types that specialize on using termites as their primary food source (for example, Priodontes and Tolypeutes).
Armadillos have poor vision, but large eyes. The armor is formed by plates of dermal bone covered in relatively small, overlapping epidermal scales called “scutes”, composed of bone with a covering of horn. In most species, rigid shields over the shoulders and hips, with a number of bands separated by flexible skin cover the back and flanks. Additional armor covers the top of the head, the upper parts of the limbs, and the tail. The underside of the animal is never armored, and is simply covered with soft skin and fur.
This armor-like skin appears to be the main defence of many armadillos, although most escape predators by fleeing (often into thorny patches, from which their armor protects them) or digging to safety. Only the South American three-banded armadillos (Tolypeutes) rely heavily on their armor for protection.
When threatened by predator, Tolypeutes Species frequently roll up into a ball. Other armadillo species cannot roll up because they have too many plates. The North American nine-banded armadillo tends to jump straight in the air when surprised, and consequently often collides with the undercarriage or fenders of passing vehicles.
Armadillos have short legs, but can move quite quickly, and have the ability to remain underwater for as long as six minutes. Because of the density of its armor, an armadillo will sink in water unless it swallows air, inflating its stomach to twice normal size and raising its buoyancy above that of water, allowing it to swim across narrow streams and ditches.
Armadillos use their claws for digging and finding food, as well as for making their homes in burrows. They dig their burrows with their claws, only making a single corridor where they fit themselves. They have five clawed toes on the hind feet, and three to five toes with heavy digging claws on the forefeet.  Armadillos have a large number of cheek teeth, which are not divided into premolars and molars, but usually have incisor canines. The dentition of the nine-banded armadillo is P 7/7, M 1/1 = 32. Gestation lasts anywhere from 60 to 120 days, depending on species, although the nine-banded armadillo also exhibits delayed implantation, so the young are not typically born for eight months after mating. Most members of the genus Dasypus give birth to four monozygotic young (that is, identical quadruplets), but other species may have typical litter sizes that range from one to eight. The young are born with soft, leathery skin, which hardens within a few weeks; they reach sexual maturity in three to 12 months, depending on the species. Armadillos are solitary animals that do not share their burrows with other adults.

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