“The omnivore—” began Marin.
Hafner nodded impatiently. “Work on it,” he said, and walked away.
The biologist sighed. The omnivore really was a queer little creature, but it was by no means the most important thing on Glade. For instance, why were there so few species of land animals on the planet? No reptiles, numerous birds, and only four kinds of mammals.
Every comparable planet teemed with a wild variety of life. Glade, in spite of seemingly ideal conditions, hadn’t developed. Why?
He had asked Biological Controls for this assignment because it had seemed an interesting problem. Now, apparently, he was being pressed into service as an exterminator.
He reached in the cage and picked up the omnivore. Mammals on Glade were not unexpected. Parallel development took care of that. Given roughly the same kind of environment, similar animals would usually evolve.
In the Late Carboniferous forest on Earth, there had been creatures like the omnivore, the primitive mammal from which all others had evolved. On Glade, that kind of evolution just hadn’t taken place. What had kept nature from exploiting its evolutionary potentialities? There was the real problem, not how to wipe them out.
Marin stuck a needle in the omnivore. It squealed and then relaxed. He drew out the blood and set it back in the cage. He could learn a lot about the animal from trying to kill it.
THE quartermaster was shouting, though his normal voice carried quite well.
“How do you know it’s mice?” the biologist asked him.
“Look,” said the quartermaster angrily.
Marin looked. The evidence did indicate mice.
Before he could speak, the quartermaster snapped, “Don’t tell me they’re only micelike creatures. I know that. The question is: how can I get rid of them?”
“Have you tried poison?”
“Tell me what poison to use and I’ll use it.”
It wasn’t the easiest question to answer. What was poisonous to an animal he had never seen and knew nothing about? According to Biological Survey, the animal didn’t exist.
It was unexpectedly serious. The colony could live off the land, and was expected to. But another group of colonists was due in three years. The colony was supposed to accumulate a surplus of food to feed the increased numbers. If they couldn’t store the food they grew any better than the concentrates, that surplus was going to be scanty.
Marin went over the warehouse thoroughly. It was the usual early construction on a colonial world. Not esthetic, it was sturdy enough. Fused dirt floor, reinforced foot-thick walls, a ceiling slab of the same. The whole was bound together with a molecular cement that made it practically airtight. It had no windows; there were two doors. Certainly it should keep out rodents.
A closer examination revealed an unexpected flaw. The floor was as hard as glass; no animal could gnaw through it, but, like glass, it was also brittle. The crew that had built the warehouse had evidently been in such a hurry to get back to Earth that they hadn’t been as careful as they should have been, for here and there the floor was thin. Somewhere under the heavy equipment piled on it, the floor had cracked. There a burrowing animal had means of entry.
Short of building another warehouse, it was too late to do anything about that. Micelike animals were inside and had to be controlled where they were.
The biologist straightened up. “Catch me a few of them alive and I’ll see what I can do.”
IN the morning, a dozen live specimens were delivered to the lab. They actually did resemble mice.
Their reactions were puzzling. No two of them were affected by the same poison. A compound that stiffened one in a matter of minutes left the others hale and hearty, and the poison he had developed to control the omnivores was completely ineffective.
The depredations in the warehouse went on. Black mice, white ones, gray and brown, short-tailed and long-eared, or the reverse, they continued to eat the concentrates and spoil what they didn’t eat.
Marin conferred with the executive, outlined the problem as he saw it and his ideas on what could be done to combat the nuisance.
“But we can’t build another warehouse,” argued Hafner. “Not until the atomic generator is set up, at any rate. And then we’ll have other uses for the power.” The executive rested his head in his hands. “I like the other solution better. Build one and see how it works.”
“I was thinking of three,” said the biologist.
“One,” Hafner insisted. “We can’t spare the equipment until we know how it works.”
At that he was probably right. They had equipment, as much as three ships could bring. But the more they brought, the more was expected of the colony. The net effect was that equipment was always in short supply.
Marin took the authorization to the engineer. On the way, he privately revised his specifications upward. If he couldn’t get as many as he wanted, he might as well get a better one.
In two days, the machine was ready.
It was delivered in a small crate to the warehouse. The crate was opened and the machine leaped out and stood there, poised.
“A cat!” exclaimed the quartermaster, pleased. He stretched out his hand toward the black fuzzy robot.
“If you’ve touched anything a mouse may have, get your hand away,” warned the biologist. “It reacts to smell as well as sight and sound.”
Hastily, the quartermaster withdrew his hand. The robot disappeared silently into the maze of stored material.
In one week, though there were still some mice in the warehouse, they were no longer a danger.
THE executive called Mann into his office, a small sturdy building located in the center of the settlement. The colony was growing, assuming an aspect of permanency. Hafner sat in his choir and looked out over that growth with satisfaction.
“A good job on the mouse plague,” he said.
The biologist nodded. “Not bad, except there shouldn’t be any mice here. Biological Survey—”
“Forget it,” said the exec.
“Everybody makes mistakes, even B. S.” He leaned back and looked seriously at the biologist. “I have a job I need done. Just now I’m short of men. If you have no objections . . .”
The exec was always short of men, would be until the planet was overcrowded, and he would try to find someone to do the work his own men should have done. Dano Marin was not directly responsible to Hafner; he was on loan to the expedition from Biological Controls. Still, it was a good idea to cooperate with the executive. He sighed.
“It’s not as bad as you think,” said Hafner, interpreting the sound correctly. He smiled. “We’ve got the digger together. I want you to run it.”
Since it tied right in with his investigations, Dano Martin looked relieved and showed it.
“Except for food, we have to import most of our supplies,” Hafner explained. “It’s a long haul, and we’ve got to make use of everything on the planet we can. We need oil. There are going to be a lot of wheels turning, and everyone of them will have to have oil. In time we’ll set up a synthetic plant, but if we can locate a productive field now, it’s to our advantage.”
“You’re assuming the geology of Glade is similar to Earth?”
Hafner waggled his hand. “Why not? It’s a nicer twin of Earth.”
Why not? Because you couldn’t always tell from the surface, thought Marin. It seemed like Earth, but was it? Here was a good chance to find out the history of Glade.
Hafner stood up. “Any time you’re ready, a technician will check you out on the digger. Let me know before you go.”
ACTUALLY, the digger wasn’t a digger. It didn’t move or otherwise displace .a gram of dirt or rock. It was a means of looking down below the surface, to any practical depth. A large crawler, it was big enough for a man to live in without discomfort for a week.
It carried an outsize ultrasonic generator and a device for directing the beam into the planet. That was the sending apparatus. The receiving end began with
a large sonic lens which picked up sound beams reflected from any desired depth, converted it into electrical energy and thence into an image which was flashed onto a screen.
At the depth of ten miles, the image was fuzzy, though good enough to distinguish the main features of the strata. At three miles, it was better. It could pick up the sound reflection of a buried coin and convert it into a picture on which the date could be seen.
It was to a geologist as a microscope is to a biologist. Being a biologist, Dano Marin could appreciate the analogy.
He started at the tip of the peninsula and zigzagged across, heading toward the isthmus. Methodically, he covered the territory, sleeping at night in the digger. On the morning of the third day, he discovered oil traces, and by that afternoon he had located the main field.
He should probably have turned back at once, but now that he had found oil, he investigated more deliberately. Starting at the top, he let the image range downward below the top strata.
It was the reverse of what it should have been. In the top few feet, there were plentiful fossil remains, mostly of the four species of mammals. The squirrel-like creature and the far larger grazing animal were the forest dwellers. Of the plains animals, there were only two, in size fitting neatly between the extremes of the forest dwellers.
After the first few feet, which corresponded to approximately twenty thousand years, he found virtually no fossils. Not until he reached a depth which he could correlate to the Late Carboniferous age on Earth did fossils reappear. Then they were of animals appropriate to the epoch. At that depth and below, the history of Glade was quite similar to Earth’s.
Puzzled, he checked again in a dozen widely scattered localities. The results were always the same—fossil history for the first twenty thousand years, then none for roughly a hundred million. Beyond that, it was easy to trace the thread of biological development.
In that period of approximately one hundred million years, something unique had happened to Glade. What was it?
On the fifth day his investigations were interrupted by the sound of the keyed-on radio. “Mann.”
“Yes?” He flipped on the sending switch.
“How soon can you get back?” He looked at the photo-map.
“Three hours. Two if I hurry.” “Make it two. Never mind the oil.”
“I’ve found oil. But what’s the matter?”
“You can see it better than I can describe it. We’ll discuss it when you get back.”
RELUCTANTLY, Marin retracted the instruments into the digger. He turned it around and, with not too much regard for the terrain, let it roar. The treads tossed dirt high in the air. Animals fled squealing from in front of him. If the grove was small enough, he went around it, otherwise he went through and left matchsticks behind.
He skidded the crawler ponderously to halt near the edge of the settlement. The center of activity was the warehouse. Pickups wheeled in and out, transferring supplies to a cleared area outside. He found Hafner in a corner of the warehouse, talking to the engineer.
Hafner turned around when he came up. “Your mice have grown, Marin.”
Marin looked down. The robot cat lay on the floor. He knelt and examined it. The steel skeleton hadn’t broken; it had been bent, badly. The tough plastic skin had been torn off and, inside, the delicate mechanism had been chewed into an unrecognizable mass.
Around the cat were rats, twenty or thirty of them, huge by any standards. The cat had fought; the dead animals were headless or disembowled, unbelievably battered. But the robot had been outnumbered.
Biological Survey had said there weren’t any rats on Glade. They had also said that about mice. What was the key to their error?
The biologist stood up. “What are you going to do about it?”
“Build another warehouse, two-foot-thick fused dirt floors, monolithic construction. Transfer all perishables to it.”
Marin nodded. That would do it. It would take time, of course, and power, all they could draw out of the recently set up atomic generator. All other construction would have to be suspended. No wonder Hafner was disturbed.
“Why not build more cats?” Marin suggested.
The executive smiled nastily. “You weren’t here when we opened the doors. The warehouse was swarming with rats. How many robot cats would we need —five, fifteen? I don’t know. Anyway the engineer tells me we have enough parts to build three more cats. The one lying there can’t be salvaged.”
It didn’t take an engineer to see that, thought Marin.
Hafner continued, “If we need more, we’ll have to rob the computer in the spaceship. I refuse to permit that.”
Obviously he would. The spaceship was the only link with Earth until the next expedition brought more colonists. No exec in his right mind would permit the ship to be crippled.
But why had Hafner called him back? Merely to keep him informed of the situation?
HAFNER seemed to guess his thoughts. “At night we’ll floodlight the supplies we remove from the warehouse. We’ll post a guard armed with decharged rifles until we can move the food into the new warehouse. That’ll take about ten days. Meanwhile, our fast crops are ripening. It’s my guess the rats will turn to them for food. In order to protect our future food supply, you’ll have to activate your animals.”
The biologist started. “But it’s against regulations to loose any animal on a planet until a complete investigation of the possible ill effects is made.”
“That takes ten or twenty years. This is an emergency and I’ll be responsible—in writing, if you want.”
The biologist was effectively countermanded. Another, rabbit-infested Australia or the planet that the snails took over might be in the making, but there was nothing he could do about it.
“I hardly think they’ll be of any use against rats this size,” he protested.
“You’ve got hormones. Apply them.” The executive turned and began discussing construction with the engineer.
MARIN had the dead rats gathered up and placed in the freezer for further study.
After that, he retired to the laboratory and worked out a course of treatment for the domesticated animals that the colonists had brought with them. He gave them the first injections and watched them carefully until they were safely through the initial shock phase of growth. As soon as he saw they were going to survive, he bred them.
Next he turned to the rats. Of note was the wide variation in size. Internally, the same thing was true. They had the usual organs, but the proportions of each varied greatly, more than is normal. Nor were their teeth uniform. Some carried huge fangs set in delicate jaws; others had tiny teeth that didn’t match the massive bone structure. At a species, they were the most scrambled the biologist had ever encountered.
He turned the microscope on their tissues and tabulated the results. There was less difference here between individual specimens, but it was enough to set him pondering. The reproductive cells were especially baffling.
Late in the day, he felt rather than heard the soundless whoosh of the construction machinery. He looked out of the laboratory and saw smoke rolling upward. As soon as the vegetation was charred, the smoke ceased and heat waves danced into the sky.
They were building on a hill. The little creatures that crept and crawled in the brush attacked in the most vulnerable spot, the food supply. There was no brush, not a blade of grass, on the hill when the colonists finished.
TERRIERS. In the past, they were the hunting dogs of the agricultural era. What they lacked in size they made up in ferocity toward rodents. They had earned their keep originally in granaries and fields, and, for a brief time, they were doing it again on colonial worlds where conditions were repeated.
The dogs the colonists brought had been terriers. They were still as fast, still with the same anti-rodent disposition, but they were no longer small. It had been a difficult job, yet Marin had done it well, for the dogs had lost none of their skill and speed in growing, to the size of a gre
at dane.
The rats moved in on the fields of fast crops. Fast crops were made to order for a colonial world. They could be planted, grown, and harvested in a matter of weeks. After four such plantings, the fertility of the soil was destroyed, but that meant nothing in the early years of a colonial planet, for land was plentiful.
The rat tide grew in the fast crops, and the dogs were loosed on the rats. They ranged through the fields, hunting. A rush, a snap of their jaws, the shake of a head, and the rat was tossed aside, its back broken. The dogs went on to the next.