1) Family castoridae 2) Mammal family 
The family Castoridae contains the two living species of beavers and their fossil relatives. This was once a highly diverse group of rodents, but is now restricted to a single genus, Castor. == Characteristics == Castorids are medium-sized mammals, although large compared with most other rodents. They are semiaquatic, with sleek bodies and webbed ...
The Castoridae is a family of rodent animals comprising the single genus, Castor (the beaver).
[n] - beavers
family Castoridae noun beavers