National Geographic : 1988 Dec
J INDOWS into the most intimate cor ners of whales' lives have given us new in sight into their courtship and mating strategies. In behavior seldom if ever witnessed (left), a male humpback at left appears to blow bubbles that will rise be neath the genitals of a female, center, accompanied by her calf. Is this a stimulation to mate? No one knows. Such gentleness con trasts with often fierce competi tion among males for a female. Right whale males, however, show less aggression toward their rivals and sometimes even appear to cooperate in mating with the same female. Off Pen insula Valdes (top) a male, at right, mates with a female as a second male waits his turn, left background. In another mating group a calf following its mother too closely is accidentally pounded by her massive flukes (right center)-a rare mishap since right whale females with calves usually avoid courting males. Its back also scuffed, an other calf rests near its mother as she appears to mate (bottom). Rather than by physical dom inance, male right whales may pass on their genes by means of sperm competition. In theory, when numerous males mate with the same female, the male with the largest testes could dis place or dilute the sperm of his rivals. And right whale males, with one-ton testes, have the highest testes-to-body-weight ratio of any baleen whale. Right whale females calve only once every three years. In austral winter the tiny newborns keep in constant motion beside their mothers for their first month. A two- to three-month play stage follows; some exas perated mothers roll over and hold their young between their flippers to quiet them. In No vember mother and calf show signs of coordinated travel be fore departing for the open At lantic ... we know not where.