Tammy Benedict, age 13, of Powellton, West Virginia, for her question:
What is the life span of a frog?
Some 2,000 different frogs are at home in various wet, green shady regions around the world. And each species has his own life style, with a reasonable time in which to grow up and grow old. Some can expect to live five, ten or even 15 years. But the frog populations provide food for numerous hungry meat eaters and in the wilds, few of them live long enough to reach old age.
Most likely the oldest frogs are those that are protected in captivity. We know that captive bullfrogs can live as long as 15 years. Ordinary green frogs often live 12 years in captivity. Some of the smaller species are old timers at the age of three or four. But none of these species would live as long in the wilds.
The frogs, of course, are cold blooded creatures who depend for warmth upon their surroundings, Living cells need warmth to carry on their chemical activities and when the temperature drops they slow down. Hence, the frogs must hibernate during the winter season. This is a risky period in the life of any frog and many do not survive their first winter.
Life is fraught with hazards from the very beginning, when the next generation begins as a batch of jellified eggs. Species that mate early often leave the eggs in deeper water, where late frosts are less likely to freeze them. Even so, countless frog eggs are devoured by fishes, turtles and hosts of other gourmets.
The pretty little black tadpoles also live risky lives in the water. However, in a few species the male or female parent carries the eggs in pockets in their skin. The protected youngsters do not leave home until the tadpoles mature to the stage of mini adults and so have a better chance of surviving, at least through the early stages.
The common leopard frog, alias the meadow frog, lays a great mass of eggs in the water, usually in April. The tadpoles take two to three months to become miniature adults, depending on the weather. Come fall the young frogs go into hibernation. They continue to grow during the following summer but are not fully mature until the age of two or three.
In certain green frog species, the tadpole stage lasts more than a year. During the first winter they hibernate in the mud at the bottom of their streams and ponds
When spring comes they soon transform their fishy gills for air breathing lungs, lose their tadpole tails and take on froggy colors by the third spring, they are mature enough to mate. The big bullfrog is in no hurry to grow up He remains in the tadpole stage through two years and sometimes through three or four. He may grow to be five, six or even eight inches long. But at last he matures. Barring accidents, the bull¬ frog has a life expectancy of fifteen years counting the time he spent as a tadpole.