North American Bullfrog

Lithobates catesbeianus

Identification

The North American Bullfrog is one of the three similar green-faced frogs in Vermont (the others are the Mink Frog and the North American Green Frog). The North American Bullfrog is our largest frog and can reach 7 inches long (not counting the legs). It usually has a green and brown mottled body with dark stripes across its legs. Colors vary from almost pure green to pure brown with largely varying degrees of mottling as well.  The North American Bullfrog does not have dorsolateral ridges (folds of skin on either side of its back), but it does have a ridge that starts at the eye and goes around the eardrum (tympana) and down. Like the North American Green Frog, the throat of the breeding male is yellow.

The North American Bullfrog’s call is a deep, low “jum-a-rum”. It may be heard from May through August on warm nights, peaking at the start of July.

Similar to the North American Green Frog, the North American Bullfrog’s eggs form a film on the surface of the water, but both the individual eggs and the entire masses of the American Bullfrog are larger. In Vermont, the North American Bullfrog remains a tadpole through one or two winters.

Get more detailed identification and life history information by downloading the chart here.

You can learn more about this species and see some video footage by checking out this clip from our Rattlers, Peepers & Snappers DVD.

Range/Habitat

They are generally found in or near large permanent bodies of water with emergent vegetation along the shoreline. They are locally common in the Lake Champlain Basin and the Connecticut River Valley.

Status

The North American Bullfrog has a state natural heritage rank of S5 (common). However, they are more widely dispersed than other S5 species. Please report all sightings of this species in Vermont. Take photos including the back and face of the frog (or record the call) if possible. Even historic sighting information is useful.

Additional Photos

         

 

More Info

All the Vermont species listed in the Rana genus were reclassified into the Lithobates genus in 2007. The North American Bullfrog’s species name also changed from catesbeiana to catesbeianus. In 2025, the common name was changed from American Bullfrog to North American Bullfrog.

• Lithobates catesbeianus at Animal Diversity website
• Rana catesbeiana at Amphibiaweb
• Listen to its calls at Calls of Frogs and Toads of the Northeast (scroll down and click the triangular play button at the bottom left of the species photo)

Species summary written by Ariel K. Mck. Burgess.