American Bullfrog



american bull frogHave you ever wondered what was Oklahoma’s state amphibian? It is the American bullfrog (Rana caresbeiana), an aquatic frog that is native to most of North America. The American bullfrog is a member of the family Ranidae, the “true frog” family.

The bullfrog is the largest frog in the United States with an average size of four to seven inches. The record size for an American bullfrog in Oklahoma is eight inches from snout to vent and it weighed two pounds. While females are typically larger than males, males will have a larger tympanum (ear) than females. In males, the tympanum is larger than the eye, whereas in females it is the same size or smaller than the eye. Bullfrogs are well known for their enormous legs and they are some of the best jumpers in the world.

The back and sides are green to brown and dark bands are visible on the hind kegs. The hind feet of bullfrogs are webbed. During the breeding season the throat of the male will be bright yellow. In the wild they can live seven to nine years, but they can live nearly twice as ling in captivity.

American bullfrog uses its skin and lings for respiration. When a bullfrog goes underwater it can sloe its nostrils and continue to absorb oxygen through its skin. 

These frogs are appropriately named for the loud sound they make often described as a low rumbling “jug-o-rum”. Their call is loud enough to deter potential predators and attract mates. Bullfrogs also have a sense of vision and can sense vibrations. Not only are bullfrogs big and loud they are quite protective of their staked out territories and will aggressively defend them from trespassers by calls, displays, chases, jump attaches and by physically wrestling with an intruder. 

Bullfrogs prefer warm weather and will hibernate during cold weather. Bullfrogs have been known to bury themselves in mud and create small, cave-like structures for the winter. 

Breeding generally occurs from late spring to early summer, but some males have been known to call into the fall. Females are attracted to the males that have territories that provide the most food. A single female can lay up to 25,000 eggs. Females search for a quiet protected areas and will deposit the eggs in a foamy film. Fertilization is usually, but not always, by one male. Once the female has laid the eggs. There is no further parental involvement in offspring. 

Spotted tadpoles will emerge from their floating eggs mass about four days after fertilization has occurred. The newly hatched tadpoles are then able to take care of themselves right away. Initially, the tadpoles have gills and a tail, which will disappear as the tadpole begins the transformation into a froglet. The development of bullfrog tadpoles is quite slow compared to many other species; it can take one to three years to begin the adult stage. A longer tadpole stage generally means a larger frog, which will have a better chance of survival. Males and females will reach reproductive maturity at three to fives years of age. 

The American bullfrog prefers to sit and wait for their prey t come by them; then, with a quick flash of its tongue, they will grab their prey and bring it back into their large mouths, They are carnivorous and will eat virtually anything that they can overpowers and that will fit into their mouths, including crayfish, insects, frogs, reptiles, mice, birds and an occasional bat. 

Bullfrogs are found statewide near streams, rivers, ponds, lakes and swamps where the water is warm, still and shallow. They are primarily active at night but they will bask in the sun during the day. Bullfrogs are known by some for their tasty meat. Bullfrogs may be taken year-round by sportsmen with hook and line, gig, spear, bow and arrow or other methods besides firearms with a resident or nonresident fishing license. A hunting license is required to take bullfrogs with a firearm. Consult the current “Oklahoma Hunting Guide” for bag limits and other regulation.