The humpback whale (Megaptera novaeangliae) is a baleen whale that is found in oceans around the world. Reproduction is one topic that many people have studied about humpback whales and one that involves many different components.

One of the most important components involved in the reproduction of humpbackwhales is their migration pattern. Humpback whales migrate seasonally between high-latitude summer feeding areas and low-latitude winter breeding areas (7). They have incredible endurance capabilties, traveling large distances during each seasonal migration with almost no rest along the way. Humpback whale winter grounds are generally located in waters of low productivity, and during their stay in the winter grounds, humpback whales generally do not feed (7). Due to their migration patterns, reproduction is strongly seasonal, with peaks of spermatogenesis and ovulation occurring during the winter. The primary function of migration is believed to be as a reproductive display to attract potential mates (1).

Once they have arrived at the winter breeding areas, intense competition begins between the males. Due to the lack of food availability on the winter grounds, energy constraints faced by males force them to compete over females with high reproductive potential rather than females that are less likely to bear a calf the following year. The most commonly observed aggressive behavior is the head lunge, during which a whale thrusts its head forwards out of the water, often with the throat area inflated (7). In some cases, forceful contact occurs between competing males, resulting in bloody wounds.

Another way that males attract females is through their singing. Humpback whales are known for their singing, something that is done only by males and something that primarily occurs in the winter breeding grounds. While in their winter breeding areas, humpbacks sing lengthy, complex songs- some lasting as long as thirty minutes (6). Although much of the reasoning behind the singing is unknown, many scientists believe that the singing relates to male reproductive success and some even believe that the singing acts to synchronize ovulation in females (3).

The primary reason behind male competition is that despite the common belief that whales are monogamous, humpback whales practice polygyny. Humpback whales do not form stable pair bonds during the winter breeding season. Females are seen with multiple males and males are seen with multiple females throughout each breeding season, forcing males to compete for the most fertile females (1).

In a study done by Campbell et al., Microsatellite DNA markers were used to examine the paternity of calves born to individually identified mature female humpback whales from the Gulf of Maine. Skin biopsies were obtained from three females, and several of their known offspring (1). The following results were obtained:

Results showed that offspring of the same mother had different fathers, indicated by the presence of at least three different paternal alleles. The results, which demonstrate the occurrence of promiscuous mating, are to be expected given current knowledge of the social ecology of this species (1). It is also consistent with re-sightings of individually identified female humpbacks with different male associates during two or more breeding seasons.

Humpback whales are truly amazing creatures that will probably never be fully understood. Due to the hard work of researchers and scientists we understand more about these creatures today than we ever have before, and hopefully we will only continue to understand more about these amazing creatures in the future.

Works Cited

1. Clapham, Phillip J., and Per J. Pallsboll. "Molecular Analysis of paternity shows promiscuous mating in female humpback whales." Proceedings of the Royal Society B: Biological Sciences (1997): 1-4. Print.


2. Craig, Alison S., and Louis M. Herman. "Sex differences in site fidelity and migration of humpback whales (Megaptera novaeangliae) to the Hawaiian islands." Canadian Journal of Zoology (1997): 1-11.


3. C. S. Baker and L. M. Herman, Aggressive behavior between humpback whales (Megaptera novaeangliae) wintering in Hawaiian waters. Canadian Journal of Zoology 62 (1984), pp. 1922–1937.


4. C. S. Baker, L. M. Herman, A. Perry, W. S. Lawton, J. M. Straley, A. A. Wolman, G. D. Kaufman, H. E. Winn, J. D. Hall, J. M. Reinke and J. Ostman, Migratory movement and population structure of humpback whales (Megaptera novaeangliae) in the central and eastern North Pacific. Marine Ecology Progress Series 31 (1986), pp. 105–119.


5. P. J. Clapham, The social and reproductive biology of humpback whales: an ecological perspective. Mammal Review 26 (1996), pp. 27–49.


6. Cerchio, Salvatore, Jeff K. Jacobsen, and Thomas F. Norris. "Temporal and geographical variation in songs of humpback whales, Megaptera novaeangliae: synchronous change in Hawaiian and Mexican breeding assemblages." Animal Behaviour 62.2 (2001): 313-29.


7. Craig, A.S., Herman, L.M., & Pack, A.A. (2002). Male mate choice and male-male competition coexist in the humpback whale (Megaptera novaeangliae). Canadian Journal of Zoology 80, 745-755