His return homeward at daybreak was caused by no intelligent fear of his keeper, but by a perfectly natural instinct inherited from his ancestors, namely, that of retiring during the day to his own favourite den or lurking-place, as an ogre is supposed to ensconce himself in his castle or cavern after having satiated his rapacious maw in a successful foray. For it must be remembered that the octopus is nocturnal in its habits, and ordinarily hides itself as much as possible during the day, shrinking from the light, which is apparently disagreeable to it: its wanderings in search of food, therefore, generally take place at night.[16] Although I had once seen the octopus in question crawl out of the water on to the rocks above the surface in the daytime, and had often witnessed his activity during the dark hours, and the surprising rapidity of his progress by crawling or walking, he had not been seen to do all of which he was accused. Every opportunity was, therefore, given to him of continuing his incursions into his neighbours’ compartment, and it was hoped that he would be caught in the act. So acute, however, are these creatures in their perceptions, so quick of sight, and so sensitive to the light of even a distant lantern, that our suspected pirate would not start on a buccaneering expedition whilst anyone was cruising in the building. He seemed to know that he was watched; and for about a week remained quietly at home. During that time no more young lump-suckers were missing. Then he again broke bounds, and, moreover, prevailed on one of his class-mates to follow his bad example of going out on the loose.