Ancestors of Our Mammals
The wild horses that Bodo saw were about the size of ponies.
Long before the Tree-dwellers lived there were horse-like creatures the size of a fox.
Long before that there was a time when there were no horses at all.
Great reptiles moved about on the land, they swam in the seas, or they flew through the air.
All other creatures feared them.
The tiny mammals that lived then were about the size of rats and mice, but these mammals were not like rats and mice.
The little mammals ran, but they did not run fast, for their feet were not well fitted for running.
They climbed rocks and trunks of trees, and hid in holes in the ground.
They ate the eggs of the large reptiles, and became their enemies.
A reptile
Millions of years passed; great changes took place.
Parts of the land slowly sank beneath the seas, and out of the seas rose dry land.
Most of the larger reptiles died, but the mammals multiplied.
They grew to be as large as the fox or the sheep.
At first they were all very much alike and they lived in about the same way.
But as they became more and more unlike they had very different ways.
Some became like cats, and some like dogs.
An ancestor of our mammals
Some became like rhinoceroses and some like hogs.
Others became like monkeys, and still others became like horses.