<P> Courtship rituals take place during the winter months, following migration toward the equator from summer feeding grounds closer to the poles . Competition is usually fierce . Unrelated males, dubbed escorts, frequently trail females, as well as cow - calf pairs . Males gather into "competitive groups" around a female and fight for the right to mate with her . Group size ebbs and flows as unsuccessful males retreat and others arrive . Behaviors include breaching, spyhopping, lob - tailing, tail - slapping, pectoral fin - slapping, peduncle throws, charging and parrying . </P> <P> Whale song is thought to have an important role in mate selection; however, they may also be used between males to establish dominance . Polyandry has been observed in humpback whales, with the females having multiple male partners throughout their lifespan . </P> <P> Females typically breed every two or three years . The gestation period is 11.5 months . The peak months for birth are January, February (northern hemisphere), July and August (southern hemisphere). Females wait for one to two years before breeding again . Recent research on mitochondrial DNA reveals that groups living in proximity to each other may represent distinct breeding pools . Humpback whale births have been rarely observed . One birth witnessed off Madagascar occurred within four minutes . </P> <P> Humpbacks are a friendly species that interact with other cetacean species such as bottlenose dolphins . Right whales interact with humpbacks . These behaviors have been recorded in all oceans . Records of humpback and southern right whales demonstrating what were interpreted to be mating behaviors have been documented off the Mozambique and Brazilian coasts . Humpback whales appear in mixed groups with other species, such as the blue, fin, minke, gray and sperm whales . Interaction with gray, fin, and right whales have been observed . Teams of researchers observed a male humpback whale singing an unknown type of song and approaching a fin whale at Rarotonga in 2014 . One individual was observed playing with a bottlenose dolphin in Hawaiian waters . Recently, incidents of humpback whales protecting other species of animals such as seals and other whales from killer whales has been documented and filmed . Studies of such incidents indicate that the phenomenon is species - wide and global, with incidents being recorded at various locations across the world . In September 2017 in Rarotonga, the Cook Islands, two adult humpback whales were observed protecting snorkeler and whale biologist Nan Hauser from a 4.5 m (15 ft) tiger shark, with one whale pushing the woman away from the shark while the other used its tail to block the predator's advances . This may be the first recorded incidence of humpback whales acting protective over a human . </P>

How long is the gestation period for humpback whales