Pakaeocastor
Group Early Oligocene to Early Miocene
Size 40cm long
Location USA, Japan
Palaeocastor was one of the earliest known relatives of living beavers. It lived between the Early Oligocene and the Early Miocene. Fossils have been found in western USA and Japan. Although related to beavers, Palaeocastor was not an aquatic tree-cutter. Instead it was a terrestrial burrower, about the size and shape of a modern marmot.