Bruce Bagemihl - Biological Exuberance

Frequency: In captive Musk-oxen, about 40 percent of courtship behavior and 10 percent of mounting activity is homosexual. A little over a quarter of wild, nonbreeding males associate in pairs. In Mountain Goats, nearly 18 percent of courtships during the breeding season are between adult and yearling males; about 8 percent of courtship displays outside of the breeding season occur between two adult males. In one study, 1 out of 14 mounts (7 percent) performed by yearling Mountain Goats on their mothers were same-sex, involving a female offspring.

Orientation: Some younger male Musk-oxen may participate exclusively in homosexual activity, since most males do not breed until they are older than six. In contrast, yearling male Mountain Goats that are courted by older males are primarily heterosexual, since they reject most same-sex advances. The majority of adult male Musk-oxen and Mountain Goats that court other males are probably bisexual, since they also court females and usually do so more often than they court males.

Although male Musk-oxen become sexually mature by the time they are two years old, most bulls do not mate heterosexually for another five years because older males generally monopolize breeding opportunities in the female herds. Even among older males, less than half—and often as few as one-quarter—actually participate in procreation. The remainder are nonbreeding bulls that are often solitary or associate with other males in pairs or small groups, sometimes wandering far from the herds. The rate of calf production is low in this species (females usually reproduce every other year), and entire populations may forgo breeding in some years. Even during breeding years, some heterosexual courtship activity in both Muskoxen and Mountain Goats may be directed by males toward nonprocreating individuals such as yearlings and calves. In addition, male Mountain Goats sometimes court and mount females outside the breeding season or even court females in the act of giving birth. Females in this species have been observed mounting adult males and courting, mounting, or being mounted by their own yearlings or kids. Relations between the sexes are often marked by strife. Females of both species sometimes reject the courtship and mounting attempts of males. Male Musk-oxen may become violent during their courtship kicks of females (the impact of the blow against a female’s spine or pelvis can be considerable). As many as two-thirds of Musk-ox mounts may not culminate in ejaculation, because the male is anatomically unsuited to remaining mounted on the female (he is considerably heavier than her and unable to clasp with his forelegs during a mount). Among Mountain Goats, females are often notably aggressive toward males, attacking and sometimes viciously wounding them with stabs from their sharp horns. In addition, violence toward calves has been observed among Musk-oxen: females sometimes flip calves other than their own into the air with their horns, while males have been known to gore calves.

In the distantly related Himalayan Tahr ( Hemitragus jemlahicus ), intersexuality sometimes occurs: one individual, for example, had testes and the general appearance of a male combined with a vulva, enlarged clitoris, and a female chromosome pattern.

*asterisked references discuss homosexuality/transgender

*Benirschke, K. (1981) “Hermaphrodites, Freemartins, Mosaics, and Chimaeras in Animals.” In C. R. Austin and R. G. Edwards, eds., Mechanisms of Sex Differentiation in Animals and Man, pp. 421–63. London: Academic Press.

Chadwick, D. H. (1983) A Beast the Color of Winter: The Mountain Goat Observed. San Francisco: Sierra Club Books.

*———(1977) “The Influence of Mountain Goat Social Relationships on Population Size and Distribution.” In W. Samuel and W. G. Macgregor, eds., Proceedings of the First International Mountain Goat Symposium, pp. 74–91. Victoria, B. C.: Fish and Wildlife Branch.

*Geist, V. (1964) “On the Rutting Behavior of the Mountain Goat.” Journal of Mammalogy 45:551–68.

Gray, D. R. (1979) “Movements and Behavior of Tagged Muskoxen ( Ovibos moschatus ) on Bathurst Island, N.W.T.” Musk-ox 25:29–46.

———(1973) “Social Organization and Behavior of Muxkoxen ( Ovibos moschatus ) on Bathurst Island, N.W.T.” Ph.D. thesis, University of Alberta.

*Hutchins, M. (1984) “The Mother-Offspring Relationship in Mountain Goats ( Oreamnos americanus ) .” Ph.D. thesis, University of Washington.

Jingfors, K. (1984) “Observations of Cow-Calf Behavior in Free-Ranging Muskoxen.” In D. R. Klein, R. G. White, and S. Keller, eds., Proceedings of the First International Muskox Symposium, pp. 105–9. Biological Papers of the University of Alaska Special Report no. 4. Fairbanks: University of Alaska.

Lent, P. C. (1988) “Ovibos moschatus.” Mammalian Species 302:1–9.

*Reinhardt, V. (1985) “Courtship Behavior Among Musk-ox Males Kept in Confinement.” Zoo Biology 4:295–300.

*Smith, T. E. (1976) “Reproductive Behavior and Related Social Organization of the Muskox on Nunivak Island.” Master’s thesis, University of Alaska.

*Tener, J. S. (1965) Muskoxen in Canada: A Biological and Taxonomic Review. Ottawa: Canadian Wildlife Service.

IDENTIFICATION: An enormous buffalo (up to 6½ feet high) with massive forequarters, humped shoulders, and (in males) a beard. DISTRIBUTION: Formerly throughout north-central North America, now only in protected areas. HABITAT: Grassland, forests. STUDY AREAS: National Bison Range, Montana; Catalina Island, California; Wind Cave National Park, South Dakota; Wichita Mountain Wildlife Refuge, Oklahoma; Yellowstone National Park, Wyoming; Mackenzie Bison Sanctuary, Northwest Territories, Canada; Waterhen Wood Bison Ranch, Manitoba, Canada; Steel Rose Ranch, Saskatchewan, Canada; subspecies B.b. bison, the Plains Bison, and B.b. athabascae, the Wood Bison.

IDENTIFICATION: Similar to American Bison but more slender, less hunched, and with longer legs. DISTRIBUTION: Formerly throughout Europe and central Asia, now only in protected areas; endangered. HABITAT: Forests. STUDY AREAS: Białowieża Primeval Forest and Reserve, and Niepotomice Reserve, Poland; Polish Academy of Sciences.

IDENTIFICATION: A huge (II-foot-long), usually black buffalo with massive, upward-curving horns in both sexes. DISTRIBUTION: Sub-Saharan Africa. HABITAT: Savannas, forests. STUDY AREA: Serengeti National Park, Tanzania; subspecies S.c. caffer, the Cape, or Steppe, Buffalo.

Adult males (bulls) in American and European Bison generally live separately from females in groups that may contain up to 12 animals, or else solitarily. Females, their calves, and younger males (generally less than three or four years old) all live together in their own groups. For two months out of the year, female groups aggregate and adult males join these larger herds (which may contain hundreds of animals) for the rutting season. The mating system is “serial monogamy” within an overall framework of polygamy, i.e., males mate with several females, but remain exclusively with each female for a short period. African Buffalo have a similar social organization, living in herds ranging in size from 40–1,500 animals, mostly composed of females and their young in family groups, along with some adult males for part of the year. In addition, about 15 percent of adult males live in smaller bachelor herds, and older males may form peripheral groups.