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How are armadillos related to sloths and anteaters?

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Nine-banded armadillo (Dasypus novemcinctus). — armadillo Nine-banded armadillo (*Dasypus novemcinctus*).

Armadillos, sloths, and anteaters are all members of the ancient mammalian lineage known as the magnorder Xenarthra.12

These animals share a unique anatomical feature in their lower backbone called "xenarthrous" vertebrae. These extra joints strengthen the lower back and hips, which supports the use of their forelegs for activities such as digging. Additionally, all xenarthrans share similar physiological traits, including low metabolic rates and lower body temperatures compared to other mammals of similar size.1

While they share a common ancestry, they are classified into distinct orders:
* Order Cingulata: Includes the armadillos, characterized by their girdle-like shells.1
* Order Pilosa: Includes sloths and anteaters, a group named for their hairiness.1

Originating in South America during the Paleocene Epoch, these groups were once more diverse and widespread, including extinct forms like ground sloths and glyptodonts.1