Maria Heymann, age 10, of Lancaster, Pa., for her question:
HOW MANY EGGS DOES A FROG LAY?
Many people enjoy a tasty meal of frog legs, though frog eggs are not on our menus. However, fishes and lots of other wild creatures regard frog eggs as a tasty treat. Every spring, zillions of those little black balls in their gobs of clear jelly become part of nature's food chain. So naturally the frogs lay lots of extras to make sure that some survive to grow up.
An adult frog is a small amphibious animal with a super long tongue, bulging eyes and long back legs. He is called an amphibian because his life cycle includes a tour of duty in the water when he is young and later a place in the sun as a full fledged air breathing animal.
His life begins as an egg in a freshwater pond or lake. The mother frog generally lays her eggs in one large clump, usually fastened to a waterweed. The number of eggs she lays and the place she lays them depend on what kind of frog she is. The little wood frog of Canada lays about 1,000 eggs in ponds that may still have ice on them. The American bullfrog may deposit as many as 20,000 in one huge egg mass.
The eggs generally hatch from four to 15 days after they are laid, and the emerging creatures look like tiny raisins with tails. At this stage they are called tadpoles, and their kindergarten days are spent in the water. They live the life of fish, breathing much as fish do with gills.
If food is scarce, the tadpoles may take many weeks to grow and develop into frogs. But if they have plenty of waterweeds and pond scum, most tadpoles become frogs in a couple of months. First the hind legs appear, then the front legs and finally the tadpole's tail begins to disappear. But before a new frog is ready to take his first leaps on land, he must exchange his gills for a pair of air breathing lungs.
We share our continent with dozens of different frogs, and each species has its own idea of family life. Some lay a few hundred eggs, here and there, in the moist woods. Others lay floating masses in the water. Most of them lay between 2,000 and 3,000 during the summer season. Most of these eggs and most of the tadpoles become food for fishes and turtles, snakes and birds, beetles and spiders.