Distantly related to sloths and anteaters, armadillos evolved in South America during the mammal explosion of the early Tertiary Period, some 50-60 million years ago. When the Isthmus of Panama formed, about 3 MYA, some species moved into Central America; today, all but 2 of the 20 modern species of armadillo inhabit South America and the nine-banded armadillo is the only one found in the United States.
Since crossing into Texas in the late 1800s, nine-banded armadillos have rapidly expanded their range; limited by dryness and poorly equipped to survive in prolonged cold, these prolific mammals can be found from western Oklahoma to the Atlantic Seaboard and from southern Kansas, southern Missouri and South Carolina to the Gulf Coast. Favoring streamside habitat, the armadillo army has spread along the Arkansas and Lower Mississippi Valleys and inward from the Gulf and Southern Atlantic Coasts via rivers and streams of the broad Coastal Plain; they have also been transplanted to some areas in the Southeast.
Armadillos mate in mid summer and, after delayed implantation and four months of pregnancy, identical quadruplets are born in early to mid spring; able to forage soon after birth, they nurse for two months and are sexually mature by the following summer. Powerful diggers, armadillos feast on earthworms, insects, grubs, fruit and carrion and excavate dens in which to sleep, give birth or to wait out periods of cold weather. Though often victims of dogs, coyotes and automobiles, armadillos may live 15 years or more and their range is expected to expand into the Mid Atlantic States over the coming decades.