That they should remain up there, hard pressed by hunger and the lack of shelter, when nothing prevented them from going away, seemed to me unthinkable foolishness. Facts, however, forced me to accept the incredible.
The Caterpillars keep on marching round the vase for hours and hours. As evening comes on, there are more or less lengthy halts; they go more slowly at times, especially as it grows colder. At ten o’clock in the evening the walk is little more than a lazy swaying of the body. Grazing-time comes, when the other Caterpillars come crowding out from their nests to feast on the pine-needles. The ones on the vase would gladly take part in the feast; they must have an appetite after a ten hours’ walk. A branch of pine is not a hand’s breadth away from them. To reach it they have only to go down the vase; and the poor wretches, foolish slaves of their ribbon that they are, cannot make up their minds to do so. At half-past ten I leave them to go to bed; I am sure that during the night they will come to their senses. At dawn I visit them again. They are lined up as on the day before, but motionless. When the air grows a little warmer, they shake off their torpor, revive, and start walking again in their circle.
Things go on as before during the next day. The following night is very cold. The poor Caterpillars spend a bad night. I find them clustered in two heaps on the top of the vase, without any attempt at order. They have huddled together to keep warm. Perhaps, now that they are divided into two parts, one of the leaders, not being obliged to follow a Caterpillar in front of him, will have the sense to break away. I am delighted to see them lining up by degrees into two distinct files, with two leaders, free to go where they please. At the sight of their large black heads swaying anxiously from side to side, I am inclined to think they will leave the enchanted circle. But I am soon undeceived. As the ranks fill out, the two sections of the chain meet and the circle is formed again. Again the Caterpillars march round and round all day.
The next night is again cold, and the Caterpillars gather in a heap which overflows both sides of the fatal ribbon. Next morning, when they awake, some of them who find themselves outside the track actually follow a leader who climbs to the top of the vase and down the inside. There are seven of these daring ones. The rest pay no attention to them and walk round the circle again.
The Caterpillars inside the vase find no food there, and retrace their steps along their thread to the top, strike the procession again, and slip back into the ranks.
Another day passes, and another. The sixth day is warm, and for the first time I see daring leaders, who, drunk with heat, stand on their hind-legs at the extreme edge of the vase and fling themselves forward into space. At last one of them decided to take the plunge. He slips under the ledge and four follow him. They go halfway down the vase, then their courage fails and they climb up again and rejoin the procession. But a start has been made and a new track laid. Two days later, on the eighth day of the experiment, the Caterpillars—now singly, then in small groups, then again in strings of some length—come down from the ledge by starting on this fresh path. At sunset the last of the Caterpillars is back in the nest at the foot.
I figure that they have walked for eighty-four hours, and covered a good deal more than a quarter of a mile while traveling in the circle. It was only the disorder due to the cold nights that ever set them off the track and back to safety. Poor, stupid Caterpillars! People are fond of saying that animals can reason, but there are no beginnings of a reasoning power to be seen in them.
