Aptly named for its deep, resonant croak, the American bullfrog (Lithobates catesbeianus) is North America’s largest frog species. This impressive, golden-eyed amphibian has a broad head and body, and its rough skin is covered in tiny, randomly arranged tubercles. The tips of the American bullfrog’s fingers and toes are blunt, and the webbing between the digits is well developed. The colouration of the American bullfrog varies widely depending on the location, with its upperparts ranging from bright green to olive or brownish green. A netlike pattern of brown or grey markings may be present on its back. The hind limbs are long and powerful and have dark blotches and bands. The underside of the American bullfrog is much paler than the upperparts, with a cream or whitish belly that is tinged with yellow or mottled with grey. As well as being larger than the male, the female American bullfrog is also generally browner and more highly spotted. The throat of the male is yellow, while that of the female is white, and a further difference between the sexes is the presence of pigmented ‘nuptial pads’ on the thumbs of the male, which are used to grip the female during mating. As with the adults, the tadpoles of the American bullfrog are large. The back of the tadpole is yellowish green, speckled with black spots, and has an arched dorsal fin, while the belly is lighter. The American bullfrog is named for its deep, resonant croak. Known for its voracious appetite, the American bullfrog eats almost anything it can swallow. The American bullfrog is considered to be one of the 100 worst invasive species in the world.
