Bull frog at Sacramento National Wildlife Refuge Complex

An Ark for Amphibians

Bullfrog Action Group

California's battle to control non-native bullfrogs

U.S. Fish and Wildlife Service - Northern river otters love fish

Sacramento National Wildlife Refuge

Bullfrogs to become state's amphibious illegal alien – Daily Democrat

WISC - Washington Invasive Species Council

Bullfrog Action Group

The precarious persistence of the Endangered Sierra Madre yellow

Sacramento county hi-res stock photography and images - Page 2 - Alamy

American Bullfrog (Lithobates catesbeianus) - Species Profile