Filtering whales, unlike the gregarious porpoises and dolphins, seldom
school. Even when they appear to be abundant in a limited area, they
have congregated for feeding and not for social interaction. Toothed
cetaceans, on the other hand, are generally sociable. The sperm whale
travels in large groups of females dominated by a single bull whale. The
other males have been driven away and the victorious male exercises
control of the harem only as long as he wins these contests. Once the
dominant male is defeated, he becomes a solitary individual.