Muskrat
- Photographs of this aquatic species that is related to the beaver, and notes on its physical and other characteristics.
- http://www.holoweb.com/cannon/muskrat.htm

Amazing Animals: Beaver
- Information on this industrious mammal which can fell a tree with a diameter of 30 cm in a single night.
- http://www.bbc.co.uk/nature/reallywild/amazing/beaver.shtml

Beavers: Wetlands and Wildlife
- Introduction to the biology of Castor canadensis and advice on resolving conflicts between humans and beavers.
- http://www.beaversww.org/

Castoridae Family
- Information about the family and detailed accounts of its two species from the Animal Diversity Web.
- http://animaldiversity.ummz.umich.edu/site/accounts/information/Castoridae.html