American bullfrog

The American bullfrog (Lithobates catesbeiana, formerly Rana catesbeiana) is a common species of large frog which spends most of its time in and close to water. Though native to the southeastern United States and adjacent areas of the eastern and midwester states, bullfrogs have been introduced to many areas in North, Central and South America as well as Western Europe and parts of Asia, often as a source of food. They are sometimes also bred commercially for food, and for use in education.

In some areas outside their native range, including the US west coast and Hawaii, bullfrogs are considered an invasive species which threaten other native frogs. Because bullfrogs are less susceptible than many other amphibians to chytridiomycosis (infection of the chytrid fungus), they may help spread the disease.

Bullfrogs mate from March to August, with males using their distinctive low, loud call to claim territory and to attract females. During breeding season males congregate in "choruses" to join voices in a more impressive call, but individuals protect a territory of 5 to 10 feet in any direction, with older more dominant males in the center of the group. Male bullfrogs are smaller than females and have yellow throats and large visible eardrums. The largest females can weigh more than a pound and exceed 6 inches in body length. While males breed continuously, females only visit during brief periods for copulation.

The species is considered of the lowest conservation concern by the International Union for Conservation of Nature. The species name honors 18th century English naturalist Mark Catesby who published the first catalog of North American flora and fauna.