Giant beaver

The giant beaver or castoroides ohioensis was a a giant species of rodent from the pleistocene epoch 3 mya to 11, 000 years ago. Castoroides was twice the size of a modern day beaver at 2.2 m long and 90 to 125 kilograms in weight making it one of the largest species of rodent. Castoroides wouldn't have needed to be cut down trees because it mainly ate swamp plants. Casteroides has been found in New york, ontario and the yukon territory in canada.

In the series...
Castoroides was seen in the episode prehistoric new york where it was seen eating water plants and living in a den.