Female Cuis (and less commonly, males) use a stylized form of same-sex courtship chasing known as REARING: one female approaches another and rears up on her hind legs as if to mount, then drops back down on all fours to follow the other female, repeating the pattern. Sometimes this leads to actual mounting, in which one female thrusts against the other in an upright posture behind her. Homosexual mounting is common when females are in heat, but it also occurs when a female is not in heat and even when she is pregnant. Among Apereas, females court one another by performing the RUMBA: in this courtship dance, one female rhythmically sways her hindquarters from side to side while slowly approaching, circling, or following another female. She may also make a burbling sound known as RUMBLING. Adult male Apereas sometimes court younger males by RUMPING, in which the adult throws one or both hind legs over the rump of the youngster.
Dwarf Cavies also sometimes bond with animals of the same sex, forming “companionships” and even coparenting arrangements. Two (occasionally three) females share a home (living under the same bush), frequently sitting together and kissing each other with prolonged nuzzling of mouths and noses. They may even cooperate in nursing one another’s young. Adult males occasionally also have an adolescent companion; the two males sit and feed together, as well as kiss one another. Sometimes the adult male will permit his companion to mount a female that he is courting.
Frequency: Homosexual courtships make up 58 percent of adult-juvenile chin-rump follows (and 44 percent of all such courtships) in Dwarf Cavies, while more than a third of Cui courtship rearing interactions are between females. Homosexual courtships are less common in Apereas.
Orientation: Most Cavies that participate in same-sex activities are probably bisexual. For example, adult male Apereas and Dwarf Cavies court both juvenile males and females, while same-sex bonded Dwarf Cavies usually copulate with members of the opposite sex. However, there are differences in the apparent preference of adult males for homosexual interactions: in Dwarf Cavies, the majority of adult-juvenile courtships are homosexual, while in Apereas fewer such courtships are same-sex.
Cavies regularly engage in heterosexual courtship and sexual behaviors that are nonprocreative. Female Cuis that are pregnant, lactating, or not in heat, for example, often participate in mounting and courtship (including REVERSE mounting of males). Aperea males commonly court pregnant females. Male Dwarf Cavies occasionally masturbate by sitting back on their haunches, making pelvic thrusts, and then licking and nuzzling the erect penis. As mentioned above, sexual behavior between adults and juveniles is widespread in these species. About a quarter of all courtship and sexual interactions in Dwarf Cavies involve adult males and juveniles, while adult male Cuis also chin-rump follow juvenile females as young as two weeks old. In addition, juvenile Cuis of both sexes sometimes mount both adult males and females, including their own mothers. Cui mothers have also developed an extensive system of communal nursing in which most females suckle young other than their own. Although each female nurses her own offspring for longer periods than she does others’, she may actually spend a greater total amount of time nursing nonoffspring.
Homosexual behavior occurs in several other rodents. Adult males in two other species of Cavies, the Mocó or Rock Cavy (Kerodon rupestris) and the Prea (Galea spixii), also sometimes court juvenile males, and youngsters mount adults of both sexes as well. Male Spinifex Hopping Mice (Notomys alexis) from Australia sometimes engage in sexual and bonding activities with one another, including mounting, nesting together, feeding and resting beside each other, and burrowing in tandem. Both male and female Brown Rats (Rattus norvegicus, the wild ancestor of the common household and laboratory rat) participate in homosexual mounting. Male Eastern Cottontail Rabbits (Sylvilagus floridanus) sometimes court other males in addition to females, including displays such as the JUMP SEQUENCE, in which the two males alternately rush toward and jump over one another. Males in this species also occasionally attempt to mount other males. In some populations of Kangaroo Rats (Dipodomys ordii), as many as 16 percent of the animals are intersexed, having the reproductive organs of both sexes (including a vagina, penis, uterus, and testes).
*asterisked references discuss homosexuality/transgender
*Barnett, S. A. (1958) “An Analysis of Social Behavior in Wild Rats.” Proceedings of the Zoological Society of London 130:107-52.
*Happold, M. (1976) “Social Behavior of the Conilurine Rodents (Muridae) of Australia.” Zeitschrift für Tierpsychologie 40:113–82.
Künkele, J., and H. N. Hoeck (1995) “Communal Suckling in the Cavy Galea musteloides.” Behavioral Ecology and Sociobiology 37:385–91.
*Lacher, T. E., Jr. (1981) “The Comparative Social Behavior of Kerodon rupestris and Galea spixii and the Evolution of Behavior in the Caviidae.” Bulletin of the Carnegie Museum of Natural History 17:1–71.
*Marsden, H. M., and N. R. Holler (1964) “Social Behavior in Confined Populations of the Cottontail and the Swamp Rabbit.” Wildlife Monographs 13:1–39.
*Pfaffenberger, G. S., F. W. Weckerly, and T. L. Best (1986) “Male Pseudohermaphroditism in a Population of Kangaroo Rats, Dipodomys ordii.” Southwestern Naturalist 31:124–26.
*Rood, J. P. (1972) “Ecological and Behavioral Comparisons of Three Genera of Argentine Cavies.” Animal Behavior Monographs 5:1–83.
*———(1970) “Ecology and Social Behavior of the Desert Cavy (Microcavia australis).” American Midland Naturalist 83:415–54.
Stahnke, A., and H. Hendrichs (1990) “Cavy Rodents.” In Grzimek’s Encyclopedia of Mammals, vol. 3, pp. 325-37. New York: McGraw-Hill.
IDENTIFICATION: A small (less than I foot long) insectivore with sandy-colored spines, white underparts, and prominent ears. DISTRIBUTION: Central Asia, Middle East. HABITAT: Steppe, desert. STUDY AREA: Research Laboratory for Comparative Insectivorology, Vienna, Austria; subspecies H.a. syriacus.
Long-eared Hedgehogs live in burrows and are largely nocturnal and solitary, although small groups of animals may gather at feeding or resting sites. Males take no part in parental care.
Behavioral Expression: Homosexual interactions in female Long-eared Hedgehogs involve a great deal of courtship and affectionate behaviors as well as direct sexual encounters, frequently consisting of oral sex. A typical lesbian interaction begins, often at dusk, with two females rubbing each other, sliding along each other’s body, and cuddling. One female might also crawl directly under the other, sliding back from her throat to her belly. Another courtship display involves one female stretching out full length and pressing her belly against the ground with a concave “arch” in her back. During sexual contact, females intensively lick, sniff, and nibble on each other’s genitals. Sometimes, to have better access, one female will raise the hindquarters of the other high into the air with her paws and lower jaw, lifting her partner’s hind legs clear off the ground while she continues licking. At other times, one or both females will present their raised hindquarters as an invitation for the other to mount as in heterosexual copulation. Often the presenting female is in such a state of arousal that her hindquarters are actually lifted too high for the other female to fully mount her, although she may try. In captivity, homosexual encounters have been observed between adult sisters, that is, members of the same litter.
Frequency: Homosexual interactions occur frequently between females paired together in captivity, but the incidence of this activity in wild Long-eared Hedgehogs is not known.
Orientation: Female Long-eared Hedgehogs may have a latent capacity for bisexual or homosexual behavior, since same-sex activity surfaces when females are kept together without males. However, it appears that this may initiate a preference for homosexuality that can be long-lasting: one pair of females who courted and had sex with each other refused to participate in heterosexual activity for more than two years after they were separated, although eventually both did mate with males and reproduce.
Oral-genital stimulation is a frequent component of heterosexual encounters in Long-eared Hedgehogs, with males licking and sniffing the female’s genitals. Cannibalism also occurs in this species: animals may eat already dead hedgehogs or else kill them directly and then devour them.
Homosexual activity occurs in several species of Tree Shrews, a group of animals found in Southeast Asia and thought to have affiliations with insectivores (and possibly also primates). In Common Tree Shrews (Tupaia glis), for example, about a third of all sexual activity occurs between females, including sexual approaches and following, genital licking and sniffing, and mounting. Same-sex mounting has also been observed in Slender Tree Shrews (T. gracilis), Mountain Tree Shrews (T. montana), and Long-footed Tree Shrews (T. longipes). In the latter species, mounting between females accounts for about 9 percent of all mounting activity. Female Long-footed Tree Shrews sometimes form consortships with one another as well; these typically last longer than heterosexual consortships (several months as opposed to several hours) and involve mutual grooming, lying on or next to each other, and sleeping together. Male and female homosexuality also occur in North American Porcupines (Erethizon dorsatum), including periods of exclusive homosexual activity among males.
*asterisked references discuss homosexuality/transgender
*Kaufmann, J. H. (1965) “Studies on the Behavior of Captive Tree Shrews (Tupaia glis).” Folia Primatologica 3:50–74.
*Kinsey, A. C., W. B. Pomeroy, C. E. Martin, and P. H. Gebhard (1953) Sexual Behavior in the Human Female. Philadelphia: W. B. Saunders.
Maheshwari, U. K. (1984) “Food of the Long Eared Hedgehog in Ravine Near Agra.” Acta Theriologica 29:133–37.
*Poduschka, W. (1981) “Abnormes Sexualverhalten Zusammengehaltener, Weiblicher Hemiechinus auritus syriacus (Insectivora: Erinaceinae) [Abnormal Sexual Behavior of Confined Female Hemiechinus auritus syriacus].” Bijdragen tot de Dierkunde 51:81–88.
Prakash, I. (1953) “Cannibalism in Hedgehogs.” Journal of the Bombay Natural History Society 51:730–31.
Reeve, N. (1994) Hedgehogs. London: T. and A. D. Poyser.
Schoenfeld, M., and Y. Yom-Tov (1985) “The Biology of Two Species of Hedgehogs, Erinaceus europaeus concolor and Hemiechinus auritus aegyptus, in Israel.” Mammalia 49:339–55.
*Sorenson, M.W., and C. H. Conaway (1968) “The Social and Reproductive Behavior of Tupaia montana in Captivity.” Journal of Mammalogy 49:502–12.
*———(1966) “Observations on the Social Behavior of Tree Shrews in Captivity.” Folia Primatologica 4:124–45.
GRAY-HEADED FLYING FOX
IDENTIFICATION: A large bat with an enormous wingspan (up to 4 feet), a doglike face, dark brown fur, a light gray head, and a reddish yellow mantle. DISTRIBUTION: Eastern Australia. HABITAT: Tropical and subtropical forests; roosts in trees. STUDY AREA: Near Brisbane, southeastern Queensland, Australia.
LIVINGSTONE’S FRUIT BAT
IDENTIFICATION: Similar to Gray-headed, except coat is black with tawny shoulders and groin; wingspan over 3 feet. DISTRIBUTION: Anjouan and Mohéli Islands, Comoros Archipelago (Indian Ocean); critically endangered. HABITAT: Upland forests. STUDY AREA: Jersey Wildlife Preservation Trust, England.
IDENTIFICATION: A small bat with grayish brown fur and pointed ears. DISTRIBUTION: Northern Mexico through central Chile, Argentina, Uruguay; Trinidad. HABITAT: Forests, open areas; roosts in caves, tree hollows. STUDY AREAS: Hacienda La Pacifica and Parque Nacional de Santa Rosa, Costa Rica; University of the West Indies, Trinidad.
Gray-headed Flying Foxes live in groups known as CAMPS, which may contain many thousands of individuals. These camps are segregated by sex for most of the year: males and females roost in separate trees—or in separate locations within the same tree—except during the breeding season (generally March-April). Some individuals become nomadic, solitary, or much less gregarious following the breeding season. Livingstone’s Fruit Bats appear to have a polygamous mating system, in which males mate with multiple female partners but do not participate in raising their offspring. Vampire Bat colonies may contain up to 2,000 individuals, although most have 20–100. The female group is the primary social unit, consisting of 8–12 females (many of whom are related to each other) and their young. Males sometimes form “bachelor” groups of up to 8 individuals, or they may roost in the same tree with female groups.
Behavioral Expression: Gray-headed Flying Foxes of both sexes engage in a form of mutual homosexual grooming and caressing when they are in their separate camps. One animal wraps its wings around another of the same sex in an embrace, licking and gently biting the chest and wings of its partner, rubbing its head on the other’s chest, and grooming it with its claws. Males may have an erection while they do this, and individuals generally utter a continuous pulsed, grating call while engaged in this activity. Livingstone’s Fruit Bats participate in similar forms of grooming and other homosexual activities. Combined with bouts of intense body licking—either mutual or one-sided—both males and females in this species sometimes lick, nuzzle, and sniff the genitals of a same-sex partner (one male was even seen to drink another’s urine as part of this activity). Clasping, play-wrestling, and gentle mouthing or biting of the partner occur as well. This may lead to homosexual mounting, in which one Bat grips the other from behind, holding the scruff of its neck in its mouth (as in heterosexual mating, although males do not usually experience erections or penetration during same-sex activity). Females sometimes mount their adult daughters and vice versa. In one instance, a daughter repeatedly approached, pursued, and mounted her mother for extended periods, and even successfully fought off males who were interested in mating with her mother.