Bullfrog Life Cycle

Bullfrogs pass through several stages of development during their relatively brief life cycles. As most people already know, Bullfrogs are amphibians so they begin as eggs.

In fact, an adult female frog will lay 20,000, even up to 25,000 eggs at one time – on water. This huge egg mass appears to be a kind of “floating white sheet” as it moves lazily on top of the water. It is also a target for predators and, in fact, many eggs are eaten before they get a chance to hatch.

After a period of a few days, the surviving eggs all hatch and release newly-born tadpoles (also known as polliwogs) to the world. The tadpoles which have long, narrow bodies and a tail, will spend their first winter, and often much longer, as tadpoles. During this period, they’ll live exclusively in water and eat only water plants. They will also begin to grow, store fat in their tails and breathe through newly-formed gills.

It can take as long as 2 to 3 years of growth and metamorphosis before a tadpole becomes a mature frog. However, after about one year, a young tadpole will grow legs and then, after the passage of a little more time, it will also grow arms. This is the beginning of the transformation that will turn the tadpole into a frog. The tadpole’s tail begins to shorten, it develops lungs and its gills disappear. However, it continues to live in water.

During its next stage, the tadpole turns into a froglet -- an almost fully mature frog. By this time, the soon-to-be mature frog breathes oxygen and can hop around on land. However, it still has a tail which is now very small.

After a period of 2-3 years, the transformation of egg to frog is complete. The adult Bullfrog now lives on land and no longer in water. As a newly-mature frog it has grown to about two-and-a-half inches long (older mature frogs may be as long as 6 ½ inches) and weighs as much as four pounds or more.

The adult Bullfrog is carnivorous and aggressive. It eats just about anything it can fit into its mouth – insects, small mammals, birds, fish, other frog species, even smaller Bullfrogs. It rests during the day, usually at the water’s edge and it hunts after dark. And the tail that has been a part of its body since it hatched has disappeared (it actually has been absorbed by the frog’s body).

The life of the adult, mature Bullfrog will continue this way until it dies. Rest by day, hunt for prey at night. Mating will take place when the male’s “bellow” attracts a female. And, after a period of 7 to 9 years, the adult Bullfrog’s life cycle will end.

However, while the average life cycle is in the range of 7 to 9 years, the record for longevity goes to a Bullfrog in captivity – an amazing thirteen years. Of course, frogs, in the wild or in captivity, tend to live longer in warmer climates than when the weather is cold.