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OTHER PRIMATES

SAVANNA BABOON

IDENTIFICATION: The familiar baboon, with variable coat color (greenish to yellowish brown to grayish black), doglike head with a black face, and long tail (over 2 feet in males). DISTRIBUTION: Equatorial, eastern, and southern Africa. HABITAT: Scrub, savanna, woodland. STUDY AREAS: Gombe Stream National Park, Tanzania; Ishasha Forest and Queen Elizabeth National Park, Uganda; Amboseli National Park, and near Gilgil and the Athi River, Kenya; Cape of Good Hope Nature Reserve, South Africa; Namibia; subspecies P.c. anubis, the Olive Baboon; P.c. ursinus, the Chacma Baboon; and P.c. cynocephalus, the Yellow Baboon.

HAMADRYAS BABOON

IDENTIFICATION: A gray baboon with a striking silver-gray “cape” or shoulder mane in adult males. DISTRIBUTION: Somalia, Ethiopia, southern Saudi Arabia, Yemen. HABITAT: Semidesert, steppe, savanna woodlands, rocky terrain. STUDY AREAS: Erer-Gota region, eastern Ethiopia; Brookfield (Illinois) and London Zoos.

GELADA BABOON

identification: A brown baboon with a thick “cape” of fur in adult males; both sexes have an hourglass-shaped patch of bare skin on the chest, encircled by fleshy “beads” in estrous females. DISTRIBUTION: Northern and central Ethiopia. HABITAT: Mountain grasslands, rocky gorges. STUDY AREAS: Simien Mountain National Park, Ethiopia; Yerkes Regional Primate Research Center, Georgia; San Antonio Zoo, Texas.

Social Organization

Savanna Baboons live in groups of 30—100 containing both adult males and females. Females form the matriarchal core of each group since they remain for life, whereas males often emigrate to a new group on reaching adulthood. However, some troops are strongly inbred because individuals rarely leave. In contrast, both Gelada and Hamadryas Baboons live in large troops that include so-called HAREM groups—bands that have a single male and several females. In Geladas, the primary social bonds are between the females in such groups (most of whom are related to each other, as in Savanna Baboons), whereas in Hamadryas Baboons the primary bonds are between the male and the females. Unlike many other primates, Hamadryas females emigrate from the group while males remain (hence, most of the females in a group are not related to each other). Geladas also have “bachelor” troops of nonbreeding males, and “bachelor” Hamadryas or Gelada males sometimes associate with a harem group and may develop a close relationship with its male leader.

Description

Behavioral Expression: Homosexual mounting among both males and females occurs in all three of these Baboon species. The position used is similar to that for heterosexual copulation: the mounting animal places its hands on the mountee’s lower back and clasps the mountee’s ankles or thighs with its feet. Both sexes often make pelvic thrusts during homosexual mounts; males usually have an erection, and ejaculation does occur in at least some Savanna Baboon mounts between males. Male Savanna Baboons also sometimes fondle their own or their partner’s genitals during a same-sex mount, and male mounters may gently bite or nuzzle their partner’s neck after a homosexual mount. Male Geladas have also been observed masturbating other males. Females of these species mount each other both during “heat” and outside of their sexual cycle; about 9 percent of lesbian mounts in Savanna Baboons involve a pregnant female mounting another female. Because most Savanna and Gelada females are related to the other females in a troop, at least some homosexual activity is incestuous.

Mounting between two male Savanna Baboons in Tanzania

In Savanna Baboons, homosexual mounting occurs in a variety of contexts, including during good-natured play-fighting. However, in this species (and to some extent also in the other species) same-sex mounting is most prominent as part of a unique form of male “greeting” interaction. Whenever two males meet each other, they exchange a series of ritualized sexual behaviors that may include homosexual mounting and invitations to mount, as well as a wide variety of other sexual and affectionate contacts. One such behavior is known as DIDDLING, in which the males fondle each other’s genitals, including touching or pulling on the penis and fondling the scrotum. Males also embrace and kiss each other on the head or mouth, and may even bend down to kiss, lick, or nibble on another male’s penis or nuzzle his groin and thighs. Sometimes a male will also nuzzle another male’s back with his nose,