A beautiful, green American Bullfrog on the Sweet Marsh
in northeast Iowa. USA
The baritone call of the bullfrog is so deep and resonant, it resembles the mooing of a cow, hence its name. Only males emit this trademark “jug-o-rum” bellow, and their choruses can be heard during the day or night.
The largest of all North American frogs, this giant can grow to a length of 8 inches (20 centimeters) or more and weigh up to 1.5 pounds (750 grams). Even the tadpoles of this species can reach 6.75 inches (17.2 centimeters) in length.
They are among the most wide-ranging of all North American amphibians, found in freshwater ponds, lakes, and marshes from Nova Scotia, Canada, throughout the continental United States, and as far south as Mexico and Cuba. They have even found their way to Europe, South America, and Asia.
Bullfrogs are typically green or gray-brown with brown spots and have easily identifiable circular eardrums, or tympanum, on either side of their heads.
Nocturnal predators, they will ambush and eat just about anything they can fit in their ample mouths, including insects, mice, fish, birds, and snakes. They sit quietly and wait for prey to pass by, then lunge with their powerful hind legs, mouths open wide.
Males are highly territorial and will aggressively guard their land. Females are slightly larger than males.