As was mentioned earlier, grazing and burrowing are characteristics of plains herbivores. In such a transitional period we would expect to find an increase in burrowers and grazers as grasslands became more common. Some have radically adapted limbs and claws. Obvious cases are the common garden mole and the armadillo. The mole has powerful attachments for the muscles of the upper arm on the humerus, a bone so flattened that its width has come to match its length.
Moles also have long, broad digging claws.
The armadillo, which is also a digger but not a burrower in the same way a mole or a gopher is, has large curved claws for digging. Moles did start to become quite common in the early Miocene, so we can assume that a good burrowing environment was present. Another group which became extraordinarily common in the early Miocene of western North America was that of the ancestral pocket gopher. Direct proof that this group actually burrowed does not exist, but the abundance of fossil gophers suggests that they might have lived underground in colonies. A real surprise at Agate is the number of beaver burrows.