American Bullfrog

Photo by Karl Reimer.Lithobates catesbeianus

Identification

The American Bullfrog is one of the three similar green-faced frogs in Vermont (the others are the Mink Frog and the Green Frog). The 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 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 Green Frog, the throat of the breeding male is yellow.

The 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 Green Frog, the 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 American Bullfrog remains a tadpole through one or two winters.

Map of Vermont records for Lithobates catesbeianus

[ click image to zoom | download printable PDF ]

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 American Bullfrog has a state natural heritage rank of S5 (common). Please report sightings of this species in Vermont if you have not reported them within the last five years from a given location. Any natural history observations (feeding, migrations, road crossing areas, early or late season appearance, abnormalities, etc.) are appreciated. Photographs are always helpful, particularly if your report is the first report of this species from a town.

Additional Photos

Photo by Heather Cullen.  Photo by Cindy Sprague.  Photo by John Jose.  Photo by Roy Pilcher.  Photo by Cindy Sprague.  Photo by Megan Kane.

 

More Info

All the Vermont species listed in the Rana genus were reclassified into the Lithobates genus in 2007. The  American Bullfrog also changed its species name from catesbeiana to catesbeianus.

Species summary written by Ariel K. Mck. Burgess.