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