“I’m stiff,” confessed the boy; “that sideways wiggle seems to catch me in the small of the back.” “It catches me, too,” the professor said, comfortingly, “and almost every one else in just the same way.” “Doesn’t one ever get used to it?” “The Arabs do, and people who travel in a camel-saddle a great deal. But one caravan trip won’t toughen you, my boy, and you needn’t expect it. Camels are not ideal beasts for riding, but they are so highly specialized for desert work that nothing can take their place.” “I should think,” said Perry thoughtfully, “they could be useful on the alkali plains of our Southwest.” “Especially since camels originated there,” said the professor. “Camels did? In America? You’re joking, Uncle George!” “Certainly they did. The camel is an American citizen.” The scientist smiled. “If coming over in the _Mayflower_ gives the right to be considered one of the old American families, how about the camel? We’ve found his ancestors in the Uinta formation in Utah. What period is the Uinta, Perry?” “Upper Eocene,” the boy answered promptly. “Right,” the professor answered. “And about how long ago?” “Two million years, according to that scale you gave me on shipboard.” “Well, about two million years ago, there were four different families of camelids in America which were destined to develop. The earliest of them seems to have been a small creature called Protylopus, about a foot high.” “Weren’t there any of them in Africa or Asia?” “None have been found. No, so far as we know, the camel family is pure American. All through the Eocene they remained quite tiny creatures, no bigger than a cat. They grew a little larger during the next period, the Oligocene, becoming about the size of a sheep-dog, but of course they were much more slenderly built. It was in the age after that, however, Perry, that the ancestors of the camels spread all over America. During the first part of the Miocene, vast herds of long-necked camels, known as Alticamelus, or the giraffe-camel, roamed over the western plains, and their bones are found by thousands in the Miocene deposits of Colorado.” “Why giraffe-camels, Uncle George?” asked Perry. “A camel hasn’t anything to do with a giraffe, has it?” “Not a thing,” was the reply, “although the giraffe’s scientific name, Camelopardalis, seems to give color to the idea. No, Perry, in certain ways a giraffe is an intermediate between a deer and an antelope. Don’t forget that a giraffe always has horns, although they are only small bony growths which correspond to the bony core of a deer’s horns, and the giraffe’s male ancestors had long horns, as in deer. But the giraffe-camel of the American Miocene was just plain camel, or rather, he was on the road to cameldom. He was called a giraffe-camel because he had a long thin neck like a giraffe. He carried it straight, too, so far as we can determine, not in that bended loop effect of the modern camel.” “What happened to them?”