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Bullfrog © Robin Arnold

Bullfrogs are voracious feeders and are commonly associated with the decline of native frogs where they have been introduced.

Key Bullfrog Facts

• Largest frog in North America
• Native to Eastern and Central United States
• Have been established outside of North America and often blamed for decline of native frogs where they have been introduced
• Active at night
• Diet: insects, fish, smaller frogs, and sometimes small birds and snakes

Bullfrogs Expanding Throughout the World

When a bullfrog is stretched to its full length, it may measure up to 36 inches, making it the largest frog in North America. Native to the eastern and central United States, it has been introduced in such far flung places as Jamaica, Thailand and France. Bullfrogs are aquatic frogs, but they spend much time on land and can often be spotted at the water’s edge. 

Bullfrogs are most active at night, when they prey on insects, fish, smaller frogs and sometimes small birds and snakes. They are voracious feeders and are commonly associated with the decline of native frogs where they were introduced. When hunting, they wait for prey to show itself, then lunge, sometimes using their short front legs to stuff the prey into their mouths. 

Breeding varies throughout the range, southern populations reproducing later than northern ones. Females lay 10,000-20,000 eggs that float near the surface in a film, sometimes attaching to vegetation. Eggs hatch after 5-6 days, and tadpoles become adults after 2-5 years. 

In the 1860s, struggling journalist Mark Twain visited Calaveras County, California, where he heard about a frog-jumping contest. His 1865 story “The Celebrated Jumping Frog of Calaveras Country” was his first literary success and is celebrated annually in the town of Jubilee, which hosts a bullfrog jumping contest. More than 2,000 bullfrogs are entered each year and then returned to their native habitats.