And life. Roaring, thrashing, eating, killing life. The time researchers must have searched diligently for this place, this instant in the history of the world. No words were needed to describe or explain.
The age of reptiles. Small ones scampered by quickly to avoid the carnage falling on them. Scolosaurus, armored and knobbed like a tiny tank pushed through the reeds, his spiked tail dragging a rut in the mud. Great Brontosaurus stood high against the sky, his tiny, foolish head, with its teacup of brains, waving at the end of his lengthy neck, turned back to see what was bothering him as some message crept through his indifferent nervous system. His back humped-up, a mountain of gristle and bone and flesh and hooked to it was the demon form of Tyrannosaurus. His tiny forepaws scratched feebly against the other's leathery skin while his yards-long razor-toothed jaws tore at the heaving wall of flesh. Brontosaurus, still not sure what was happening, dredged up a quarter ton of mud and water and plants and chewed it, wondering. While high above, heaving and flapping its leathery wings, Pteranodon wheeled by, long jaws agape.
"That one's hurting the other one," Mandi-2 said. "Can't you make them stop?"
"We are only observers, child. What you see happened so very long ago and is unalterable in any way."
"Kill!" Grosbit-9 muttered, his attention captured for the very first time. They all watched, mouths dropping open at the silent fury.
"These are reptiles, the first successful animals to conquer the land. Before them were the amphibia, like our modem frogs, tied un-breakably to the water where their eggs are laid and the young grow up. But the reptiles lay eggs that can hatch on land. The link with the sea has been cut. Land has been conquered at last. They lack but a single characteristic that will permit them to survive in all the parts of the globe. You have all been preparing for this trip. Can anyone tell me what is still missing?"
The answer was only silence. Brontosaurus fell and large pieces of flesh were torn from his body. Pteranodon flapped away. A rain squall blotted out the sun.
"I am talking about temperature. These reptiles get a good deal of their body heat from the sun. They must live in a warm environment because as their surroundings get cooler their bodies get cooler…"
"Warm blooded!" Agon-1 said with shrill excitement.
"Correct! Someone, at least, has been doing the required studying. I see you sticking your tongue out, Ched-3. How would you like it if you couldn't draw it back and it stayed that way? Controlled body temperature, the last major branch on the ever-branching tree. The first class of what might be called centrally heated animals is the mammalia. The mammals. If we all go a little bit deeper into this forest you will see what I mean. Don't straggle, keep up there. In this clearing, everyone. On this side. Watch those shrubs there. Any moment now…"
Expectantly they waited. The leaves stirred and they leaned forward. A piglike snout pushed out, sniffing the air, and two suspicious, slightly crossed eyes looked about the clearing. Satisfied that there was no danger for the moment, the creature came into sight.
"Coot! Is that ever ugly," Phill-4 said.
"Beauty is in the eye of the beholder, young man. I'll ask you to hold your tongue. This is a perfect example of the subclass Proto-theria, the first beasts, Tritylodon itself. For many years a source of controversy as to whether it was mammal or reptile. The smooth skin and shiny plates of a reptile — but notice the tufts of hair between the plates. Reptiles do not have hair. And it lays eggs, as reptiles do. But it, she, this fine creature here also suckles her young as do the mammals. Look with awe at this bridge between the old class of reptiles and emerging class of mammals."
"Oh, how cute!" Mandi-2 squealed as four tiny pink duplicates of the mother staggered out of the shrubbery after her. Tritylodon dropped heavily onto her side and the young began to nurse.
"That is another thing that the mammals brought into the world," Teacher said as the students looked on with rapt fascination. "Mother love. Reptile offspring, either born live or when they emerge from the egg, are left to fend for themselves. But warm blooded mammals must be warmed, protected, fed while they develop. They need mothering and, as you see, they receive it in sufficiency."
Some sound must have troubled the Tritylodon because she looked around,) then sprang to her feet and trundled off into the underbrush, her young falling and stumbling after her. No sooner was the clearing empty than the hulking form of Triceratops pushed by, the great horns and bony frill held high. Thirty feet of lumbering flesh, its tail tip twitching as it dragged behind.
"The great lizards are still here, but doomed soon to final destruction. The mammals will survive and multiply and cover the earth. We will later discuss the many paths traveled by the mammals, but today we are going to leap ahead millions of years to the order Primates which may look familiar to you."
A taller, deeper, more tangled jungle replaced the one they had been visiting, a fruit-filled, flower-filled, life-filled maze. Multicolored birds shot by, insects hung in clouds and brown forms moved along the branches.
"Monkeys," Grosbit-9 said and looked around for something to throw at them.
"Primates. A relatively primitive group that took to these trees some fifty million years in our past. See how they are adapting to the arboreal life? They must see clearly in front of them and gauge distances correctly, so their eyes are now on the front of their heads, and they have developed binocular vision. To hold securely to the branches their nails have shortened and become flat, their thumbs opposed to strengthen their grip. These primates will continue to develop until the wonderful, important day when they descend from the trees and venture from the shelter of the all-protecting forest.
"Africa," Teacher said as the time machine once more moved them across the centuries. "It could be today, so little have things changed in the relatively short time since these higher primates ventured forth."
"I don't see anything," Ched-3 said, looking about at the sun-scorched grass of the veldt, at the verdant jungle pressing up next to it.
"Patience. The scene begins. Watch the herd of deer that are coming towards us. The landscape has changed, become drier, the seas of grass are pushing back the jungle. There is still food to be had in the jungle, fruit and nuts there for the taking, but the competition is becoming somewhat fierce. Many different primates now fill that ecological niche and it is running over. Is there a niche vacant? Certainly not out here on the veldt! Here are the fleet-footed grass eaters, look how they run, their survival depends upon their speed. For they have their enemies, the carnivores, the meat eaters who live on their flesh."
Dust rose and the deer bounded towards them, through them, around them. Wide eyes, hammering hooves, sun glinting from their horns and then they were gone. And the lions followed. They had a buck, cut off from the rest of the herd by the lionesses, surrounded, clawed at and wounded. Then a talon tipped paw hamstrung the beast and it fell, quickly dead as its throat was chewed out and the hot red blood sank into the dust. The pride of lions ate. The children watched, struck silent, and Mandi-2 sniffled and rubbed at her nose.
"The lions eat a bit, but they are already gorged from another kill. The sun is reaching the zenith and they are hot, sleepy. They will find shade and go to sleep and the corpse will remain for the scavengers to dispose of, the carrion eaters.”
Even as Teacher spoke the first vulture was dropping down out of the sky, folding its dusty wings and waddling towards the kill. Two more descended, tearing at the flesh and squabbling and screaming soundlessly at one another.
Then from the jungle's edge there emerged first one, then two more apes. They blinked in the sunlight, looking around fearfully, then ran towards the newly killed deer, using their knuckles on the ground to help them as they ran. The blood-drenched vultures looked at them apprehensively, then flapped into the air as one of the apes hurled a stone at them. Then it was the apes' turn. They too tore at the flesh.