“Patriofelis, who despite his name was not the father of all the cats, since the latter came from a different and smaller branch, must have been a very ugly customer, Perry. There was a good deal of the ruth of tooth and claw in those Eocene times, Perry, and an animal that wanted to escape being eaten had to keep a close lookout. And, since keeping a close lookout is a matter of brains, it is easy to see why those animals which had the least brains were the most easily eaten, and so the race became extinct.” “Yes,” agreed Perry, “that’s true yet. If you don’t use your brains, the other fellow gets ahead of you.” “He doesn’t exactly eat you for dinner,” said the Belgian, smiling, “but he’ll eat your dinner, or eat a dinner at your expense by making you work for him. After all, that’s the whole story of development, the quickest, the brainiest animals survived; the heavy, sluggish ones died off. Look at your friend Hyrachyus, the running rhinoceros. He was just a little heavier than the three-toed horse, so Patriofelis caught and ate him when he couldn’t catch the Mesohippus.” “It’s like the story of a battle,” the boy replied musingly. “Here’s one small beast that eats grass, and another small beast that eats flesh. The carnivore will eat the herbivore if he can catch him. So the whole family of herbivore has to learn to run faster than his enemy. The enemy, accordingly, gets bigger. Or, perhaps, the herbivore gets arms, and the carnivore has to be more powerful, with sharper teeth and claws. And so it goes on, each developing something against the other, until beast of prey or victim becomes so big or so clumsy that he can’t develop any further. Then, since neither can ever go backward over the path of progress, either all the grass-eaters get eaten up and their race becomes extinct, or they learn how to escape from the carnivore and that race dies off because it can’t catch its dinner.” Antoine nodded his head. “It is a story of battle,” he said, “a battle against other animals or a battle against cold. Look how many beasts have entered into the battle with Man, Perry, and how most of them have lost! The little wild cow was wise, and, as Kipling tells, became Man’s Third Friend, and so, to-day, the cow has developed and increased, so that there is hardly a country on the globe where the cow does not live in peace and comfort. But the Buffalo of the Plains gave fight to Man, he put down his horns and shaggy mane and bellowed his defiance. And so, Perry, beneath an inch or so of prairie soil lie the bones of hundreds of thousands of buffalo, and a few half-tame herds alone remain of the vast hordes that roamed the plains and gave food and a livelihood to the Indians.” [Illustration: _Courtesy of the American Museum of Natural History._ HERD CROSSING RED DEER RIVER, ALBERTA.] [Illustration: _Courtesy of American Museum of Natural History._ MUSEUM BOAT CAMP ON RED DEER RIVER.