It is the largest of the North American frogs and Canadian adults often reach a length of 150 mm. They may be entirely green on the dorsal portion of their bodies or they may be a mixture of shades of green and brown. Spotting patterns vary as some individuals have a great number of spots on their bodies and others are basically plain. There are no dorsolateral folds present on the body of the bullfrogs but a prominent fold does exist over the eardrum. The tadpole of this species is usually covered with small black dots on its dorsal and lateral sides with a yellowish colouration underneath.
Bullfrogs usually inhabit permanent waters of river bays, lakes and large ponds.
During mating season, the call of the bullfrog can be heard as a resounding bass. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Houghton Mifflin Company, Boston. Introduction to Canadian Amphibians and Reptiles. National Museums of Canada, Ottawa.