However, weeks went by, and then months, with no sign of a creature possessing more than the rudiments of a nervous system. Had the men understood the operation of the lensless, many-spined “eyes” of the local animals they might have been more hopeful; but as it was most of them grew resigned to facing a job of several lifetimes. It was sheer chance that when a thinking creature finally did turn up it was discovered by the robot. Had it been the other way around—if the native had discovered the machine—history could easily have been very different on several planets.

The creature, when they did see it, was big. It towered fully nine feet in height, and on that planet must have weighed well over a ton. It conformed to the local custom as regarded scales and number of limbs, but it walked erect on two of the appendages, seemed not to be using the next two, and used the upper four for prehension. That was the fact that betrayed its intelligence; two long and two shorter spears, each with a carefully chipped stone head, were being carried hi obvious readiness for instant use.

Perhaps the stone disappointed the human watchers, or perhaps they remembered what happened to metals on this planet and refrained from jumping to conclusions about the culture level suggested by the material. In any case, they watched the native carefully.

This was easier than it might have been; the present neighbourhood, many miles from the original landing point, was a good deal rougher in its contours. The vegetation was both higher and somewhat less brittle, though it was still virtually impossible to avoid leaving a trail where the robot crawled. The men guessed at first that the higher plants had prevented the native from seeing the relatively small machine; then it became apparent that the creature’s attention was fully occupied by something else.

It was traveling slowly and apparently trying to leave as little trail as possible. It was also making allowance for the fact that to leave no trail was not practicable; periodically it stopped and built a peculiar arrangement consisting of branches from some of the rarer, springy plants and the sharp stone blades which it took hi seemingly endless supply from a large leather sack slung about its scaly body.