Muskrat Skull - The muskrat, like its larger relative the beaver, is an aquatic rodent. The muskrat is an herbivore and will chew on small saplings for food as well as eating a variety of other plants. Muskrats were once heavily trapped for their fur. Decline in demand has allowed this species to overpopulate many areas. The muskrat can be found over much of North America with the exception of the Southwest. On Average, these skulls measure 2.4 inches long.