Day by day the tadpoles were carefully watched, and the following wonderful changes were observed.
When about seven weeks old, their hind legs became jointed, and long toes were formed. The tadpoles were now able to kick out and swim by means of their long hind legs. Their gills went away, and they came to the surface and took mouthfuls of air. They now had lungs instead of gills.
But the most striking change came at the end of the eleventh week.
One by one they lost the cloak which covered head and body.
Under this cloak a pair of fore legs had been folded up and hidden for some time. They were now tiny, wide-mouthed frogs, with long, clumsy tails.
The clumsy tails grew smaller and smaller daily. At last there was no tail left, and what was at one time a cluster of black, wriggling tadpoles, was now a crowd of lively little dark yellow frogs.
The boys wished to keep them longer, but their uncle told them that they could not do this.
“Your tadpoles are now frogs,” he said. “The frog is an insect eater. As we cannot give these little frogs their natural food, we must place them where they can get it for themselves, or they will die.”
So the frogs were carried back to their native pond.
1. What are tadpoles? 2. How old is the frog before his hind legs appear? 3. A tadpole seems to be all head and tail. Can you explain this? 4. How do tadpoles breathe—(1) when they are first hatched? (2) when they are four weeks old? (3) when they are eleven weeks old?
[Illustration: Frog, Toad, and Newt—showing Eggs of Toad and Newt, and Tadpoles of Frog and Toad]
“I think we had better take our newts back to the pond now, Frank.”
“Oh, do let us keep them for a day or two longer, Uncle George. They are getting quite tame.”
As he spoke, Frank drew his finger slowly round the outside of the glass vessel that held the newts. One of the creatures swam round, following his finger.
“He is hungry, and thinks you ought to have a small worm in your fingers.”
“_Thinks?_ Uncle George. Can newts _think_?”
“It looks as if they could, does it not? We feed these creatures every day, and they have got into the habit of looking for food every time we come near them. But here comes Tom with the worms.”
It was curious to watch how the newt acted when a tiny worm was given it. At first it seemed not to see the worm, although it was wriggling at his nose. It crept back slowly about two or three inches, then all at once it sprang upon the worm and gobbled it up.