There are probably not many people in the world who do not know what an armadillo looks like, their mental picture usually relates to the nine banded armadillo that is found in parts of the United States: but there are over twenty different species of armadillo. Originating in South America they are mammals, most closely related to sloths and the anteaters.
The Mayan story of their creation is that they were made to teach two unruly deities humility. Hachakyum, the Mayan sun god, sat the two disobedient gods on stools, which he then turned into armadillos, which jumped into the air, tumbling the gods to the floor. Early Spanish explorers had never seen anything like the armadillo, and the literal translation of the name is "little armored thing".
All species of armadillo have a shell over their body that is made of true bone, and many also have armor on their tails. The armor means that they are not very flexible and only the three-banded armadillo can roll itself into a ball for protection. The other species do use the armor for protection but do not roll up into a ball; in most cases the armadillo just leaves the area, its enemies bouncing off the shell. They may dig a hole to escape into as well. The armadillo's short strong legs and claws give them serious digging ability and they can quickly dig a hole in which to shelter, or find food.
Armadillos are omnivorous; they eat anything that crosses their path. Most species rely mainly on insects and small mammals for their food, and they will tear apart rotten logs in pursuit of beetles and grubs. All species can eat plant material as well and a giant armadillo getting into a field can cause devastation in a farmer's crop. This basic diet means that they do not need complicated dental arrangements and just have peg shaped molars at the rear of their mouths. They are the only mammals with teeth that are not covered in enamel.
Armadillos have very poor eyesight, relying on smell and sound to find their food.
Many species of armadillo are under threat due to agriculture and human encroachment. In particular the Giant Armadillo has been hunted for food and as a pest until it is almost extinct, and the small pink fairy armadillo is almost impossible to find in its native habitat of the Argentinean desert.
The only species that seems to be overcoming this challenge is the nine-banded armadillo, which since 1850 has expanded its range into the United States, it has been seen as far north as Illinois, but is unlikely to expand into cold areas on a permanent basis as armadillos carry very little body fat and so have a low resistance to cold. The insect food they rely on is absent in the colder months.
Some unusual features of the nine-banded armadillo have aided this expansion. They can hold their breath for four to six minutes and can cross rivers and streams by walking along the bottom. Armadillos can swim; it is thought they overcome the weight of their shells by gulping air into the intestines, making a sort of flotation device out of their own bodies.
Female armadillos in isolation in captivity have given birth over two years after their capture, showing that they can delay implantation of the embryo in some way until conditions for rearing offspring are ideal. Unique in the world is the fact that female nine-banded armadillos always give birth to four genetically identical offspring, every time. The young are born with soft shells that harden up through the laying down of bone (ossification).
The prolific digging of the armadillo has made it into somewhat of an urban pest in some areas, the only way to prevent this is to try and armadillo proof your fences, but they have been known to dig under; or set humane traps and get wildlife services to remove them. Armadillos are kept as pets in some states, but you should check with your local authorities, as it is illegal to keep them in other States.