The recent formation of the Isthmus of Panama allowed a few members of the family to migrate northward into southern North America by the early Pleistocene, as part of the Great American Interchange.

Two species, the northern naked-tailed armadillo and nine-banded armadillo, are found in Central America; the latter has also reached the United States, primarily in the south-central states (notably Texas), but with a range that extends as far east as North Carolina and Florida, and as far north as southern Nebraska and southern Indiana.

The nine-banded armadillo prefers to build burrows in moist soil near the creeks, streams, and arroyos around which it lives and feeds.

[18] The armor is formed by plates of dermal bone covered in relatively small overlapping epidermal scales called "scutes" which are composed of keratin.

[20] Most species have rigid shields over the shoulders and hips, with a number of bands separated by flexible skin covering the back and flanks.

[21] This armor-like skin appears to be an important defense for many armadillos, although most escape predators by fleeing (often into thorny patches, from which their armor protects them) or digging to safety.

When surprised, the North American nine-banded armadillo tends to jump straight in the air, which can lead to a fatal collision with the undercarriage or fenders of passing vehicles.

[24] Gestation lasts 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),[25] but other species may have typical litter sizes that range from one to eight.

[21] Armadillos are often used in the study of leprosy, since they, along with mangabey monkeys, rabbits, and mice (on their footpads), are among the few known species that can contract the disease systemically.

[31] The nine-banded armadillo also serves science through its unusual reproductive system, in which four genetically identical offspring are born, the result of one original egg.

This is the only reliable manifestation of polyembryony in the class Mammalia, and exists only within the genus Dasypus and not in all armadillos, as is commonly believed.

[33] Even though they have a leathery, tough shell, armadillos, (mainly Dasypus) are common roadkill due to their habit of jumping 3–4 ft vertically when startled, which puts them into collision with the underside of vehicles.

[35] Wildlife enthusiasts are using the northward march of the armadillo as an opportunity to educate others about the animals, which can be a burrowing nuisance to property owners and managers.

In certain parts of Central and South America, armadillo meat is eaten; it is a popular ingredient in Oaxaca, Mexico.

[39] Shel Silverstein wrote a two-line poem called "Instructions" on how to bathe an armadillo in his collection A Light in the Attic.