Western toad

The Western toad (Anaxyrus boreas) is a species of toads. They are among the largest toads. They can grow up to 5.6 and 13 cm long. They live in western North America.

References
http://www.fs.fed.us/database/feis/animals/amphibian/bubo/all.html 

Books
 (2004) The history of a Nearctic colonization: Molecular phylogenetics and biogeography of the Nearctic toads (Bufo). Evolution 58: 2517–2535.
This article is based on a description from A Field Guide to the Reptiles and Amphibians of Coastal Southern California, Robert N. Fisher and Ted J. Case, USGS. 

Other websites

Category:Toads
Category:Frogs of North America