A very large species of frog (Rana Catesbiana), found in North America; -- so named from its loud bellowing in spring.
largest North American frog; highly aquatic with a deep-pitched voice
The American Bull Frog (Lithobates catesbeianusFrost, Darrel R. 2006. Amphibian Species of the World: an Online Reference. Version 4 (17 August 2006).