Bullfrog

The bullfrog (Lithobates catesbeianus), commonly known as the American bullfrog, is a large frog native to eastern North America. It is among the largest ranid frogs; adults typically range from 7.5 to 15 cm in body length, with females larger than males and weights approaching half a kilogram. Coloration is variable, usually olive to brown or green on the dorsum, often with darker markings. The tympanum is large, typically larger than the eye, and the hind legs are strong for jumping and swimming.

Native range and range expansion: Bullfrogs occur across eastern North America, from southern Canada to Florida and west to the Mississippi River basin. They inhabit ponds, lakes, marshes, and slow-moving streams, and are well adapted to a range of habitats including agricultural and urban environments. They have been widely introduced outside their native range and now occur in many parts of Europe, Asia, Africa, and Oceania, where they can become invasive.

Biology and behavior: Bullfrogs breed in spring and early summer. Males establish calling sites and produce deep, resonant calls to attract females. Eggs are laid in large gelatinous masses in calm water. Tadpoles are omnivorous and can take one to three years to metamorphose, depending on temperature and food supply. Adults are opportunistic predators, feeding on insects, crustaceans, fish, amphibians, and small mammals. They are strong swimmers and can tolerate a range of aquatic conditions.

Ecology and human interactions: In introduced regions, bullfrogs can outcompete native frogs and spread disease, contributing to declines of local amphibians. They are listed as Least Concern globally, though some local populations face threats from habitat loss and disease. They are also harvested for food in some areas and used in scientific research.