"I think he must have had a mate, perhaps a family, nearby," replied John.  "I have read that the mother and her babies always go up into a tree to sleep, while the father squats down at its base to guard them, and here he sleeps with one eye open and the other closed, as the saying is.  At least he arouses at the slightest sound of an enemy.  We probably awakened him by our shouts while in bathing, and being so close to him when we came back along a slightly different path, he thought we were going to attack the family upstairs, and showed fight right away."