Lynn Nuding, Age 12 Of Havana, I11., for her question:
What was mesohippus?
He was an animal. Of the remote past. But mesohippus was not a hippopotamus of the Mesozoic era. He was an ancestor midway on the family tree of the horse. The first Part of his name means middle. The second part comes fry hippos, the greek word for Horse, which lives on the word hippapotomus, meaning horse of the river. The mesozoic era was the middle era of the story of life on earth. It came to a c1ose some 60 million years ago with the decline of the dinosaurs. The warm blooded Mammals had appeared. They were still ratty little creatures, but among them were the ancestors of all the mammals of the modern world. One of them was the ancestor of the Nob1e horse. His fossilized remains have not been found, but experts are sure that he walked on five toed feet.
Our fossil records of the horse family begin with eohippus, whose name means the dawn horse. His home was North America, and he lived in the balmy eocene period, some 50 million years ago. Eohippus stood 11 inches high at shoulder level. He had already lost several toes, a step toward developing that one strong toe on each foot which was to become a hoof. Eohippus had three toed hind feet and four toed front feet.
The horse family developed gradually through 50 million years from eohippus to Equus, father of the modern horse. The long story has been divided into 10 stages. With each advance, the horse has been given a different name. After 10 million years, Eohippus gave rise to orohippus who was several inches ta11er. He was also beginning to 1ose the fourth toe on each of his front feet.
Mesohippus is a horsey ancestor of the oligieene period who lived some 30 million years ago. He stood 18 inches high and ran on three toed feet. Mesohippus, the middle Horse, was the greatest horse of his day, midway to becoming the noble horse of modern times. Several horses developed during the cool, dry myocene period, and some of the lines died out. The first hoofed horse was plesippus who arose in the past million years. He gave rise to equus whose children are the horses and donkeys, the ponies and zebras of the modern world. The horse got his start in North America, and here the family developed for more Than 50 million years. Several branches of the family wandered into Asia, Europe and Africa and thrived there. We do not know why, but tragedy overtook the original stock. Sometime during the last ice ages, all the native horse perished from their homeland.