Bruce Bagemihl - Biological Exuberance

Frequency: Male Walruses engage in homosexual activities frequently during the summer haul-outs: approximately a quarter of all social interactions of males in the shallow waters involve same-sex affectionate, courtship, or sexual behaviors. On average, each male participates in such activity roughly five times per hour when in the water, and contact between males (including sexual and courtship behaviors) occupies about 3 percent of the overall time spent by males in the water. Up to 2 percent of the total male population (which may number more than 3,000) may be in the water at any one time engaging in homosexual activities. During the breeding season, up to a third of mounting activity may take place between younger males or between adult and younger males, and 2-19 percent of singing males have a younger male companion “shadowing” them.

Orientation: Because male Walruses achieve sexual maturity approximately four years before they actually participate in breeding, a sizable segment of the population is probably involved exclusively in homosexuality for a portion of their lives. Roughly 40-60 percent of all sexually mature males—those between the ages of 10 and 14—do not participate in heterosexual mating, and a large proportion of these males engage in homosexual activity. Most older males are seasonally bisexual, courting and copulating with females during the mating season and participating in same-sex activities during the summer and early fall; some, however, also engage in same-sex mounting and companionships during the breeding season.

As noted above, male Walruses experience a delay in their breeding careers, since most do not begin mating heterosexually until about 40 percent of their maximum life span is over. Once they do begin procreating, often only a small percentage of males actually copulates each year, perhaps as few as a quarter of all adult males. Among females, about half of the individuals over the age of 23 are nonbreeding, experiencing a postreproductive or “menopausal” period that may last for 7 or more years. Because of their long pregnancy (15-16 months) and nursing period (two years), most breeding-age females do not reproduce every year. One reason the pregnancy is so long is because of DELAYED IMPLANTATION: after mating, the fertilized egg fails to implant in the uterus and temporarily stops developing, remaining in “suspended animation” for four to five months. This results in an even longer period that the two sexes are separated. Although their social life is characterized by extensive sex segregation (see above), Walruses do sometimes copulate outside of the mating season. Heterosexual matings have been recorded in nearly all months of the spring and fall. Because males have a distinct yearly sexual cycle—their testes are essentially dormant except during January-March—most of this sexual activity is nonreproductive. Even during the mating season, Walruses participate in a variety of nonprocreative sexual behaviors. REVERSE mountings, in which the female clasps the male from behind and mounts him, occur in the water, and younger, sexually immature individuals also mount each other. Females have also been observed sucking their partner’s penis as well as kneading it to erection with their flippers prior to copulation (in captivity). Outside of the breeding season, males masturbate by stroking their penis with a front flipper, sometimes accompanied by knock sounds or STRUM calls (the latter sounding something like the strumming of fingers on a guitar or zither). In addition, interspecies heterosexual copulations with Gray Seals have been seen in captivity.

As in many other polygamous mammals, female Walruses generally raise their young on their own, occasionally supplemented with a number of alternative parenting arrangements. Unrelated females and males may assist in the care and protection of calves, nursery groups of youngsters sometimes play together while their mothers are occupied during the mating season, and orphaned calves are commonly adopted by other mothers or nonbreeding females. Occasionally, females even try to steal or “kidnap” calves from other females. Unfortunately, the lives of a calf and its mother are often endangered by male violence. Calves are sometimes gored by a male’s tusks, while mass tramplings may occur on haul-out sites—often triggered by belligerent Walrus bulls roaming through groups of females and their young. In some locations, such stampedes occur regularly, littering the beach with hundreds and even thousands of carcasses each year. Nearly a quarter of all fatalities are calves less than six months old, while 15 percent are aborted fetuses.

*asterisked references discuss homosexuality/transgender

Born, E.W., and L.Ø.Knutson (1997) “Haul-out and Diving Activity of Male Atlantic Walruses (Odobenus rosmarus rosmarus ) in NE Greenland.” Journal of Zoology, London 243:381-96.

Dittrich, L. (1987) “Observations on Keeping the Pacific Walrus Odobenus rosmarus divergens at Hanover Zoo.” International Zoo Yearbook 26:163-70.

Eley, T. J., Jr. (1978) “A Possible Case of Adoption in the Pacific Walrus.” Murrelet 59:77-78.

Fay, F. H. (1982) Ecology and Biology of the Pacific Walrus, Odobenus rosmarus divergens Illiger . North American Fauna, no. 74. Washington, D.C.: U.S. Department of the Interior, Fish and Wildlife Service.

———(1960) “Structure and Function of the Pharyngeal Pouches of the Walrus (Odobenus rosmarus L.).” Mammalia 24:361-71.

*Fay, F. H., G. C. Ray, and A. A. Kibal’chich (1984) “Time and Location of Mating and Associated Behavior of the Pacific Walrus, Odobenus rosmarus divergens Illiger.” In F. H. Fay and G. A. Fedoseev, eds., Soviet-American Cooperative Research on Marine Mammals, vol. 1: Pinnipeds, pp. 89-99. NOAA Technical Report NMFS 12. Washington, D.C.: U.S. Department of Commerce.

Fay, F. H., and B. P. Kelly (1980) “Mass Natural Mortality of Walruses (Odobenus rosmarus) at St. Lawrence Island, Bering Sea, Autumn 1978.” Arctic 33:226-45.

*Mathews, R. (1983) “The Summer-Long Bachelor Party on Round Island.” Smithsonian 14:68-75.

Miller, E. H., (1985) “Airborne Acoustic Communication in the Walrus Odobenus rosmarus.” National Geographic Research 1:124-45.

*———(1976) “Walrus Ethology. II. Herd Structure and Activity Budgets of Summering Males.” Canadian Journal of Zoology 54:704-15.

*———(1975) “Walrus Ethology. I. The Social Role of Tusks and Applications of Multidimensional Scaling.” Canadian Journal of Zoology 53:590-613.

*Miller, E. H., and D. J. Boness (1983) “Summer Behavior of Atlantic Walruses Odobenus rosmarus rosmarus (L.) at Coats Island, N.W.T. (Canada).” Zeitschrift für Säugetierkunde 48:298-313.

Nowicki, S. N., I. Stirling, and B. Sjare (1997) “Duration of Stereotyped Underwater Vocal Displays by Male Atlantic Walruses in Relation to Aerobic Dive Limit.” Marine Mammal Science 13:566-75.

Ray, G. C., and W. A. Watkins (1975) “Social Function of Underwater Sounds in the Walrus Odobenus rosmarus.” Rapports et Procès-Verbaux des Réunions, Conseil International pour l’Exploration de la Mer 169:524-26.