Hal Clement - Cycle of Fire

“So that’s the story!” one of the biologists breathed at last. Neither he nor any of his colleagues had been affected by the sight as Kruger had been. Of course, none of them had the same personal feeling about Dar. “I suppose we should have expected quite a lot of offspring from each individual, if this is their only means of reproduction. The population of this planet must be something terrific right: after the season change.”

One of the other biologists shook his head negatively.

“That part is all right,” he said, “but something else isn’t. Right now we’re just before one of the changes, and there are still plenty of animals around — carnivores as well as plant eaters — and the vegetation doesn’t look particularly moth-eaten. I’m afraid I can’t quite believe that there’s no other method of reproduction here.”

“Wouldn’t the need for that depend on the length of time between seasons? If this ratio is the usual one it simply means that about one individual out of fifty lives through the season.”

“Right, and the season now ending lasts about forty Earth years. I refuse to believe that such a large proportion of survivors could be expected in any wild animal over such a period. We know that they eat about as much, compared to their weights, as similar animals on Earth. How about it, Dar? Don’t new animals get started at various times during your life span?”

“Certainly,” replied the native. “Any part of an animal will grow a whole new one, provided it is big enough. The animals we use for food certainly do that, anyway; we always leave some of the creature, for that purpose. Isn’t it that way with your animals?”

“Hmph. There are some creatures on Earth capable of that sort of thing, but they’re fairly primitive forms. I don’t see how anything on this planet could get killed.”

“Well, some animals don’t leave enough of their prey to grow again, of course. Then there are always things like starvation or drowning, though starvation takes a long time to shrink anything down to the point where it can’t live.”

One of the scientists looked thoughtfully at his own right hand, on which two fingers were represented by stumps — the relic of a childhood accident. “I suppose, Dar, that it would be foolish to ask whether your own race shares this ability of regeneration.”

“I do not see why it is foolish. Yes, we have it; though in a civilized community there is, of course, very seldom any need for it. Occasionally a victim of a glider crash or something of that sort will have to replace an arm or leg.”

“Or head?”

“That is a special case. If the injury is one that interrupts the regular life processes the tissues go back to the ‘beginning’ and reorganize to a completely new individual — or to several. As far as the original individual is concerned death has occurred. As I said, this sort of thing happens rarely.”

It rather surprised the biologists, that an explanation to the phenomenon was found. However, several weeks’ work with all the facilities the Alphard had to offer did give a reasonable answer. Richter, head of the biological crew, was glad of the chance to explain it to Commander Burke. That officer had come to question him specifically on such matters; he was worried.

“I’m bothered a trifle about these people, Richter,” Burke opened the conversation. “As you know, every ship commander that goes out from Earth gets a long briefing about the risk of introducing new species in any environment. They tell us about rabbits in Australia and Japanese beetles in North America, until we get sick of the whole business of ecology. It seems to me that we’ve run into something that might possibly be a serious competitor for humanity, if what I’ve been told about Dar Lang Ahn’s people is correct.”

“I suppose you’ve read our summary about regeneration. I admit that these people are rather remarkable in some respects, but I shouldn’t say they constituted any sort of danger.”

“Why not? Don’t they fit right into the picture — a creature entering a new environment, where its natural enemies are absent, and multiplying unchecked? These beings would swamp men out in a few years.”

“I can’t see it. Dar’s people have the same natural enemies as men — any sort of meat-eating animal, as well as their usual diseases. They do have sickness, according to Dar. Anything like that would come with them.”

“But the primary killing agent that affects the race is heat. What’s going to happen if they get established on Earth, or Thanno, or Hekla, or any of a score of other worlds you and I could name? They’d be virtually immortal.”

“Granting that they need heat to die ‘normally,’ I think you’re forgetting something. They also need it to reproduce.”

“Either that, or dismemberment. What happened in the Chesapeake in the days when the oystermen thought they could get rid of starfish by chopping them up and throwing them back in the water?”

“You miss the point, Commander — and I’m afraid young Kruger has missed it, too. The really important fact is that Dar Lang Ahn’s people have to die in order to reproduce. Have you thought of it that way?” There was a long silence before the commander answered.

“No, I can’t say that I have. That does put another color to the whole situation.” He paused again in thought. “Have you any idea of why this occurs — or rather, since it’s an obvious evolutionary development for a planet like this, how it occurs?”

“We have. It was hard to figure, mostly because there is a good deal of evidence that this drastic climate change only started to occur in the last ten million years or so, but a certain organism of our own planet gave us the lead.”

“What? What creature of Earth is exposed to anything like the conditions met with here?”

“None, so far as I know; that wasn’t the sort of lead. One of the men — Ellerbee, as I recall — was working with a group of ‘hot’ animals that we’d obtained in the usual way, in one of our biggest conditioned cages. He was trying to determine whether the carnivores usually left enough of their victims to reproduce, and incidentally to see the regeneration process which Dar had told us about — we didn’t really know whether it applied to the ‘hot’ forms or not. Naturally Ellerbee was doing his best to keep track of the types and numbers of animals present, and he was a bit surprised, after a while, to find some creatures he hadn’t seen before. Fortunately he didn’t simply write the matter off as a slip in his earlier observations; he checked it carefully, and found that when the atmosphere and temperature change occurred it was possible to get animals from soil samples in which no ‘parents’ had been present.”

“Which means?”

“That some of the ‘hot’ forms reproduce by some form of microscopic spore which survives in the soil during the unfavorable season. Whether any of the ‘cold’ ones can do the same is still uncertain; we haven’t found any.”

“And what does this imply?”

“It got Ellerbee suspicious of the general theory that Dar Lang Ahn and those fire-blooded starfish are actually alternate generations of the same species. We talked over the matter at one of our regular discussion sessions and found that there was already some more evidence in. Dan Leclos had found in one type of animal a number of small, bony spheroids which experiment had showed to be the source of the ‘hot’ generation for that particular species. If they were removed before exposing the creature to heat and nitrogen dioxide no descendants appeared, although the flesh behaved in the usual manner, while if the spheres themselves were exposed to the changed conditions they produced embryonic specimens of ‘hot’ life.”