catesbeianus

Lithobates catesbeianus, the American bullfrog, is a large, aquatic frog native to eastern North America. It is one of the largest true frogs, with adults typically 7–13 cm in body length and hind legs that enable jumps and swimming; maximum length can exceed 20 cm in some individuals. Coloration varies from olive to brown with dark markings; the tympanum behind the eye is large, and males possess a vocal sac.

Habitat and behavior: Bullfrogs inhabit permanent freshwater bodies such as ponds, lakes, marshes, and slow rivers, often preferring still or flowing water with aquatic vegetation. They are generally terrestrial near water and are strong territorial vocalizers, especially during breeding. They feed opportunistically on a wide range of prey, including insects, crustaceans, fish, tadpoles, and even small vertebrates.

Reproduction and development: Breeding occurs in spring or summer. Males call to attract females with deep bellowing croaks. Eggs are laid in large gelatinous masses that attach to vegetation in the water. Tadpoles metamorphose into juvenile frogs over weeks to months, with rates strongly affected by temperature and food availability.

Distribution and conservation: Native to eastern North America, from the Gulf Coast to southern Canada. It has been introduced elsewhere in North America and in Europe and Asia, where it is often regarded as an invasive species due to predation on native amphibians and competition for resources. The IUCN lists Lithobates catesbeianus as Least Concern, though local populations may be threatened by habitat loss, pollution, and disease such as chytridiomycosis.

Taxonomy and naming: The epithet catesbeianus honors the naturalist Mark Catesby; in older classifications the species is placed in Rana catesbeiana.