The 21 Basic Mammal Groups
Armadillos, Sloths, and Anteaters (Order Xenarthra)
Originating in South America about 60 million years ago, only five million years after the dinosaurs went extinct, xenarthrans are characterized by their oddly-shaped vertebrae (hence their name, which is Greek for "strange joint"). The sloths, armadillos, and anteaters that belong to this order also have the most sluggish metabolisms of any extant mammals. The males have internal testicles. Today, xenarthrans lurk on the fringes of the mammalian mainstream, but during the Cenozoic Era, they were some of the largest animals on Earth. The five-ton prehistoric sloth Megatherium, as well as Glyptodon, the two-ton prehistoric armadillo, both lived during this time.
The 21 Basic Mammal Group caches were placed for HNY21.