For Ages 13 and Up. Armadillos are small, burrowing mammals found in the Americas. They are known for their distinctive armored shells, which are made up of bony plates covered in keratin, a protein that also makes up human hair and nails. There are several different species of armadillo, including the three-banded armadillo, the pink fairy armadillo, and the nine-banded armadillo, which is the most common species found in the United States. Armadillos are known for their digging ability and their ability to roll up into a ball for protection. They are also known for carrying and spreading leprosy, although this is relatively rare.