“In a way, though not directly. Moeritherium never developed tusks from his teeth. Now you get Antoine, sometime, to show you the details of the teeth of a typical mammal. You’ll find that there ought to be forty-four. Although he had little tusks, Moeritherium kept a fairly complete set of teeth, while Paleo-mastodon, in order to get real solid tusks, was compelled to sacrifice all his incisors but four. You’ll find that the important things in paleontology are teeth and feet.”
“That’s what I always strike in books. Just why is that, Uncle George?”
“Think a bit, and figure it out for yourself.”
Perry stared at the Moeritherium skull, and tried to picture the development of life in primitive times, millions of years before the first man walked the earth.
“I suppose,” he said, after quite a long pause, “it’s because the two main things an animal had to do was to eat and to avoid being eaten. Animals with weak teeth had to give place to animals with better teeth when the food got harder to chew, and animals that were likely to be eaten had to find ways of escape. The ones with poor feet were caught and eaten, the swift ones got away.”
“You see the importance of slight differences in teeth, then?” the scientist said. “Some of these days, when you think that the details of an animal’s bones or teeth are dry learning, remember how here, on the Libyan Desert, you saw for yourself the dawn of the elephant’s tusk suggested in the slight extension of the second incisor of the Moeritherium, or the beast of Lake Moeris.”
“And were his feet like elephants’ feet, too?”
“Yes, in a measure, but with one great difference.”
“What was that?”
“Moeritherium was a marsh animal, Paleo-mastodon was not.”