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MUSK-OX

IDENTIFICATION: A large (6—8—foot—long) mammal with long, shaggy fur, humped shoulders, and massive, down-sweeping horns. DISTRIBUTION: Arctic North America and Greenland. HABITAT: Tundra and meadows. STUDY AREAS: Nunivak Island, Alaska; Thelon Game Sanctuary, Northwest Territories, Canada; University of Saskatchewan; subspecies O.m. wardi and O.m. moschatus.

MOUNTAIN GOAT

IDENTIFICATION: A stocky, 3-foot-tall, goatlike mammal with shaggy white fur and sharp horns in both sexes. DISTRIBUTION: Western North America from southeastern Alaska to western Montana. HABITAT: Steep mountain slopes, cliffs. STUDY AREAS: Cassiar Mountain Range, British Columbia, Canada; Swan Mountains and Glacier National Park, Montana; Olympic National Park, Washington; subspecies O.a. americanus, O.a. columbiae, and O.a. missoulae.

Social Organization

Musk-oxen are generally social animals, living in mixed-sex herds (usually 10–20 animals) or smaller all-male groups; some males are also solitary. Male and female Mountain Goats remain largely segregated from each other for most of the summer, females associating in groups of usually less than 15 (including their offspring). Female Mountain Goats are generally dominant to males, who are solitary or peripheral to the female groups except during the rut. The mating system for both species is polygamous or promiscuous: animals copulate with several partners, and males do not participate in parenting.

Description

Behavioral Expression: Male Musk-oxen sometimes court and mount each other. Homosexual courtship involves several of the same patterns used in heterosexual interactions: POSITIONING, in which one male stands next to the other in a standard position such as perpendicular, parallel, or head-to-tail; SNIFFING OF THE REAR, in which one male smells and inspects the anal and genital region of the other; FORELEG KICKING, where one male gently swings his front leg against another male; and CHIN-RESTING, in which the courting male places his lower jaw on top of the other male’s body. Males also mount other males from behind (as in heterosexual mating). The mounted male sometimes resists (as do females when mounted by males) but may also permit himself to be mounted. Homosexual courtship and mounting both occur among younger males, while during the rutting season adult males sometimes court younger males as well (occasionally even

A male Musk-ox courting another male with “foreleg kicking” and “chin- resting”

juveniles). Adult male Musk-oxen may also form pairlike companionships that travel, graze, and spend time together (sometimes also fighting with one another), although overt courtship and sexual behavior probably does not occur between them.

Adult male Mountain Goats court younger (yearling) males, again using the species-typical heterosexual behavior patterns: the courting male approaches the other in a crouching position, creeping on his stomach with his head stretched forward (a posture referred to as the LOW-STRETCH). He may also flick his tongue in and out of his mouth while making a soft buzzing sound, jerk his head sideways, and attempt to lick the other male’s flanks. Typically the yearling male responds aggressively to the courting adult. Adult males occasionally perform this display toward other adult males as well. In addition, yearling females sometimes mount their own mothers.

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.

Nonreproductive and Alternative Heterosexualities

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