Larry Reynolds, age 12, of Indianapolis, Indiana, for his question:
How long does a frog's tadpole stage last?
Most frogs grow from helpless tadpoles to a miniature adult stage in about two months. However, there are about 90 different frogs and toads, and each type takes its own time about growing up. The little green wood frog does not give up his tadpole days until he is almost three months old. The bullfrog does not change from his tadpole stage until the second year of his life:
Now is the time of year to find a mass of frog eggs in a pond or quiet stream. Toad eggs are black dots usually in a long rope of jelly twined round a waterweed. Frog eggs usually come in a loose mass of clear jelly full of round black dots. Let's adopt a mass of frog eggs. Their early life cycles give us a chance to watch one of the wonders of nature.
Take the jelly, some pond water, some pond scum and a few water weeds. The best kind of nursery for your brood is an old fish aquarium, which is an oblong box with glass walls. Leave the nursery in a sunny spot and keep watch. All you need do is splash in a little water each day.
I In a few days, the black dots will begin to uncurl into little half‑moon shapes. The tadpoles are starting to form. In a week or sot the little darlings will wriggle free of their jelly. Each has a round head end and a pointed tail end.
At this stage the little fellows are quite helpless. They have neither eyes nor mouths. Howevert each has a tiny sucker under the head, The little fella uses this to stick to his egg jelly or maybe a water weed. The eyes and mouth form in a few days. Then the little black wrigglers are ready to go, go, go.
Tadpoles nibble on pond scum, water weeds and any decaying material they find. If food is very scarce, the tadpoles do not grow and the tadpole stag is delayed. At ten days, your healthy, tadpoles have tails and fringes of black whiskers where their necks should be. These fringes are gills for breathing oxygen from the water. In 16 days or so, the fringes have been replaced by inside gills.
In three to four weeks, your darlings will sprout their back legs. Five weeks or so later, they sprout front legs and you will notice that their long tails are beginning to waste away. Your tad poles are beginning to look more like miniature frogs. The final change takes place when the little frogs give up their gills for air‑breathing lungs. By now they have changed color, the tails have gone and the miniature frogs need to spend most of their time on land.
It is time now to take them back to the pond where you found the frog eggs. The wonderful job of bringing up the little darlings took about two months. If after this time your tadpoles are still tadpoles, you have a batch of bullfrogs. Take them back to the pond, for they must grow fat and hibernate through the winter,