Of course they were very small, about the size of a dysentery amoeba. The individual life span was short as compared to ours but the accelerated pace of their lives balanced it out. In the beginning, something like four of our days was a lifetime. So they lived, grew, developed, evolved. They learned to communicate. They became civilized—far more so than we have, according to them. And I guess that was true. They were even able to extend their life span to something like two months.
"And to what," I inquired—but without much fire, I'm afraid; I was losing fight—"to what am I indebted for this intrusion?"
"Necessity."
It was, to them. Their sun had begun to cool. It was their eviction notice.
They had to move or adapt themselves to immeasurably harsher conditions; and they had become so highly developed, so specialized, that change of that sort would have been difficult if not impossible. And they didn't want to change, anyway. They liked themselves as they were.
The only other thing was to escape. They had to work for flight through space. And they succeeded.
There were planets nearer to them than Earth. But these were enormous worlds to them, and the conditions were intolerably harsh. They found one planet with conditions much like those on Earth a few million years back. It was a jungle world, dominated by giant reptiles—which were of no use to the folk. But there were a few, small, struggling, warm-blooded animals. Small to us, that is—they were county size to the folk.
Some genius had a great inspiration. While the environment of the planet itself was impossibly harsh and hostile, the conditions inside these warm little animals were highly suitable!
It seemed to be the solution to their problem of survival. Small, trial colonies were established. Communication with the space ships from home was achieved.