In Hawaii, humpback behavior is focused on mating and reproductive activities, whereas in Alaska, behavior is focused on feeding. The whales' social interactions reflect these different activities. Observers in Hawaii often see several small groups of two to three whales who move about together usually a mother and calf or a mother, calf, and escort male. An escort male is generally interested in mating with the female, but he is not necessarily the calf's father. We also see single males swimming alone.
Males appear to compete for females with some pretty aggressive behaviors.
In some cases, they will fill their mouths up with water we presume to make their heads heavier and then head slap each other. Larger groups of humpbacks also gather for short periods of time, generally composed of a single female and lots of males trailing behind her. Scientists believe these are competitive groups, as the trailing whales try to bump the escort male out of his position right next to the female. Escort males have developed some pretty interesting techniques to thwart the crowd of competing males. For example, sometimes the escort male will blow bubbles to create a sort of underwater screen.