Palaeocastor

Palaeocastor ('ancient beaver') is an extinct genus of beavers that lived in the North American Badlands during the late Oligocene period to early Miocene, 29.5~18.5 million years ago. Palaeocastor was much smaller than modern beavers. There are several species including Palaeocastor fossor, Palaeocastor magnus, Palaeocastor wahlerti, and Palaeocastor peninsulatus. The animals first became known on grounds of their fossilized burrows, the "Devil's corkscrews." ==Biology== thumb|left|P. peninsulates|205x205px Some members of this genus made corkscrew-shaped burrows and tunnels. Like many early castorids, Palaeocastor was predominantly a burrowing animal instead of an aquatic animal.

Fossil evidence suggests they may have lived in family groups like modern beavers and employed a K reproductive strategy instead of the normal r-strategy of most rodents.