Biological Exuberance: Animal Homosexuality and Natural Diversity

Management Service, Herndon, Va.; OCS Study MMS 88–0056, NTIS no. PB89–195556/AS. Springfield, Va.: National Technical Information Service.

*Richardson, W. J., K. J. Finley, G.W. Miller, R. A. Davis, and W. R. Koski (1995) “Feeding, Social, and Migration Behavior of Bowhead Whales, Balaena mysticetus, in Baffin Bay vs. the Beaufort Sea—Regions with Different Amounts of Human Activity.” Marine Mammal Science 11:1–45.

Saayman, G. S., and C. K. Tayler (1973) “Some Behavior Patterns of the Southern Right Whale, Eubalaena australis.” Zeitschrift fur Saugetierkunde 38:172–83.

*Tarpley, R. J., G. H. Jarrell, J. C. George, J. Cubbage, and G. G. Stott (1995) “Male Pseudohermaphroditism in the Bowhead Whale, Balaena mysticetus.” Journal of Mammalogy 76:1267–75.

*Wursig, B., and C. Clark (1993) “Behavior.” In J. J. Burns, J. J. Montague, and C. J. Cowles, eds., The Bowhead Whale, pp. 157-99. Lawrence, Kans.: Society for Marine Mammalogy.

*Wursig, B., J. Guerrero, and G. Silber (1993) “Social and Sexual Behavior of Bowhead Whales in Fall in the Western Arctic: A Re-examination of Seasonal Trends.” Marine Mammal Science 9:103– 11.

SEALS AND MANATEES

GRAY SEAL

IDENTIFICATION: A large seal (up to 7 feet in males) with an elongated muzzle and a spotted coat. DISTRIBUTION: North Atlantic waters, including northeastern North America (especially Newfoundland), Iceland, British Isles, Norway, Kola Peninsula, Baltic Sea. HABITAT: Temperate and subarctic waters; breeds and molts on rocky coasts and islands. STUDY AREA: Ramsay Island, England.

NORTHERN ELEPHANT SEAL

IDENTIFICATION: One of the largest seals, reaching a length of up to 16 feet and a weight of 5,500 pounds (in males); adult males have a prominent proboscis. DISTRIBUTION: North Pacific waters from Alaska to Baja California. HABITAT: Oceangoing; breeds and molts on islands and coasts. STUDY AREA: Ano Nuevo State Reserve, California.

HARBOR SEAL

IDENTIFICATION: A smaller, round-headed seal with grayish brown, usually spotted fur. DISTRIBUTION: Waters of the North Atlantic and North Pacific. HABITAT: Coastal reefs, sandbars, rocks. STUDY AREAS: Otter Island, Pribilof Islands, Alaska; Nanvak Bay, Cape Newenham National Wildlife Refuge, Alaska; Seaside Aquarium, Oregon; subspecies P.v. richardsi, the Pacific Harbor Seal.

Social Organization

Gray Seals are highly gregarious, congregating in large colonies for mating and molting, and in large groups to feed. In some populations the mating system is primarily polygynous, meaning that males mate with multiple partners, do not form heterosexual pair-bonds, and do not participate in parenting. However, some individuals in these areas are “monogamous” in that they mate with the same partner year after year, while in other populations the majority of individuals mate with only one partner but not necessarily the same one each year. Northern Elephant Seals are more solitary when at sea, although they form large breeding and molting aggregations in traditional areas known as ROOKERIES and also have a polygynous mating system. Harbor Seals generally congregate in mixed-sex groups on land, anywhere from a dozen to several thousand animals; they often mate in the water, however, and appear to have a polygynous mating system as well.

Description

Behavioral Expression: During the nonbreeding season, both Gray Seal and Northern Elephant Seal bulls engage in homosexual activity. Gray Seals come ashore to molt their fur, gathering in groups of up to 150 animals, no more than half a dozen of which are females. Those males who have completed their molt often roll around in pairs near the water and mount each other; bulls of all ages participate in this activity. Both adolescent and younger adult Northern Elephant Seal bulls also engage in homosexual mounting during the molt period. This occurs in shallow waters near the shore, often as a part of extended bouts of harmless play-fighting among clusters of males. Prior to and during the mating season, this activity continues among adolescent males, though it is usually no longer aquatic. Adolescent males often spend time in male-only areas that are separate from the breeding grounds. Males are attracted to the play-fighting and mounting activity in these areas and may travel up to 100 yards through the rookery to join in. Adult bulls do not participate in this activity. However, they do sometimes mount younger adolescent and juvenile males (two to four years old). Typically the older male approaches a younger male at rest, moving up alongside him and sometimes placing his front flipper over his back in the position characteristic of heterosexual copulations. Usually the younger male struggles to escape, and the mounter may try to subdue him by pressing or bouncing his neck down on top of him or biting his neck. The older male may have an erection and attempt to penetrate the younger male, but he rarely if ever succeeds. Although they prefer juveniles or adolescents, a few bulls also try to copulate with much younger animals, such as weaned pups of both sexes (who strongly resist their advances).

Homosexual activity is also prevalent in male Harbor Seals in the form of PAIR-ROLLING: two males embrace and mount each other in the water, continuously twisting and writhing about one another while maintaining full body contact. Rolling can become quite vigorous as the two animals spiral synchronously underwater and at the surface (often in a vertical position), sometimes gently mouthing or biting each other’s neck, chasing each other’s flippers, yelping and snarling, blowing streams of bubbles underwater, or slapping the surface of the water. One male usually has an erection, and the bout of courtship rolling typically ends when he mounts the other male, grasping him from behind and maintaining this position for up to 3 minutes (sometimes sinking to the bottom in shallower waters). The two males may also take turns mounting each other. Heterosexual copulations, in contrast, can occur both in the water and on land; they are not usually accompanied by pair-rolling and can last for up to 15 minutes. Although males of all ages engage in pair-rolling, most participants are adults (sexually mature individuals over six years old) or adolescents.

Two male Harbor Seals “pair-rolling” (a courtship and sexual behavior)

Same-sex courtship or sexual behavior is not found among females in these species, but two cow Seals occasionally coparent a pup. In Northern Elephant Seals, for example, two females who have each lost their own pup sometimes adopt an orphan and raise it together, or (more commonly) a cow who has lost her pup associates with a mother and shares parenting duties with her, including nursing the pup.

Finally, some adolescent Northern Elephant Seal males are transvestite, acting and looking like females. They have the body proportions of cow Seals, and they also deliberately pull in their noses so that they resemble females (who do not have the enlarged snouts that bulls do) and keep their heads low so as not to attract attention. Moving stealthily through the breeding grounds, these younger males try to copulate with females, who, nevertheless, are usually not fooled by their attempts to disguise themselves and usually do not allow them to mate. However, because most adult males are not able to mate with females, some transvestite males are actually more successful at breeding than non-transvestite males.

Frequency: Homosexual activity occurs frequently in Harbor Seals during the late spring, summer, and fall (except during the pupping season). In one two-month study period, for example, pair-rolling between males occurred daily and in total nearly 285 same-sex rolling pairs were observed (during the same period, no heterosexual matings were seen). Homosexual behavior is also common among male Gray Seals during the molting period, less frequent among Elephant Seal bulls (though it occurs at more times of