This is the largest frog in Canada and North America. The bullfrog is brilliant green and grows to a length of 20 cm. Its belly is typically white, but may be mottled with a silvery-grey flecking. The body is flat and broad, the head and eyes are large. The forelegs are short and the strong hind legs have webbed toes. A fold of skin extends around the eardrum, but there is no dorsolateral fold down the back, as in the green frog. Tadpoles are greenish-gold on the back with a light underside, sprinkled with fine yellow dots, and have flat tails, no limbs and gills. Males have a yellow throat, but the female's throat is plain.