Bruce Bagemihl - Biological Exuberance

Frequency: Homosexual mounting probably occurs only occasionally among White-tailed and Mule Deer; however, in one study of White-tails, two out of ten observed mountings were same-sex. Up to 10 percent of males are velvet-horns in some areas, although their incidence fluctuates. In some years they may constitute as many as 40-80 percent of all males in a given population. One study of a White-tailed Deer population over 14 years found that 1-2 percent of the females had antlers; overall, approximately 1 in every 1,000-1,100 does is antlered.

Orientation: Most Deer that participate in same-sex mounting probably also engage in heterosexual courtship and copulation. Gender-mixing Deer that are fertile (almost always genetically female) are usually heterosexual (i.e., they mate with genetic males), while nonfertile transgendered Deer (e.g., velvet-horns) are probably asexual or associate only with other transgendered Deer.

Deer participate in a variety of nonprocreative sexual behaviors besides homosexuality. White-tails sometimes engage in heterosexual mountings outside of the mating season, which are nonreproductive for two reasons. They often do not involve penetration, and bucks have a seasonal sexual cycle, so that during the spring and summer their testes are small and produce little, if any, sperm. Mating episodes among Mule Deer during the breeding season often involve the male performing extensive non-insertive sexual activity prior to actual copulation: in this activity he mounts the female with his penis erect (unsheathed) but without penetration. These mounts may be fairly lengthy—up to 15 seconds—and frequent (anywhere from 5 to more than 40 in one session). Bucks of both species sometimes masturbate in a unique fashion: the penis is first unsheathed and licked, then stimulated by moving it back and forth (via pelvic rotations and thrusts) in its sheath or against the belly until orgasm is reached. Because their antlers are actually sensitive—even erotic—organs (as in several other species of Deer), buck Mule Deer also sometimes sexually stimulate themselves by rubbing their antlers on vegetation. Incestuous activity—including fawns mounting their mothers—also occurs in these species.

As mentioned above, sex segregation is a notable feature of White-tailed Deer society. This pattern usually begins during the fawning period, when does become aggressive toward adult males and may even kick and chase them away. When their male fawns become yearlings, females also drive them away in the same violent fashion. In addition to nonbreeding transgendered animals, other nonreproducing individuals occur. White-tail bucks often do not mate until they are three to five years old; because of the physical stresses of reproduction, bucks that delay breeding may actually grow larger than those that reproduce earlier. When breeding does occur, females of both species sometimes terminate their pregnancies by aborting the fetus or reabsorbing the embryo. This probably occurs in 1-10 percent of Mule Deer pregnancies, but is more likely to happen when unfavorable climate and forage would make it difficult for mothers to feed and care for their young.

*asterisked references discuss homosexuality/transgender

*Anderson, A. E. (1981) “Morphological and Physiological Characteristics.” In O. C. Wallmo, ed, Mule and Black-tailed Deer of North America, pp. 27-97. Lincoln and London: University of Nebraska Press.

*Baber, D. W. (1987) “Gross Antler Anomaly in a California Mule Deer: The ‘Cactus’ Buck.” Southwestern Naturalist 32:404-6.

Brown, B. A. (1974) “Social Organization in Male Groups of White-tailed Deer.” In V. Geist and F. Walther, eds., The Behavior of Ungulates and Its Relation to Management, vol. 1, pp. 436-46. IUCN Publication no. 24. Morges, Switzerland: International Union for Conservation of Nature and Natural Resources.

*Cowan, I. McT. (1946) “Antlered Doe Mule Deer.” Canadian Field-Naturalist 60: 11-12.

*Crispens, C. G., Jr., and J. K. Doutt (1973) “Sex Chromatin in Antlered Female Deer.” Journal of Wildlife Management 37:422-23.

*Donaldson, J. C., and J. K. Doutt (1965) “Antlers in Female White-tailed Deer: A 4-Year Study.” Journal of Wildlife Management 29:699-705.

*Doutt, J. K., and J. C. Donaldson (1959) “An Antlered Doe With Possible Masculinizing Tumor.” Journal of Mammalogy 40:230-36.

*Geist, V. (1981) “Behavior: Adaptive Strategies in Mule Deer.” In O. C. Wallmo, ed., Mule and Black-tailed Deer of North America, pp. 157-223. Lincoln and London: University of Nebraska Press.

*Halford, D. K., W. J. Arthur III, and A. W. Alldredge (1987) “Observations of Captive Rocky Mountain Mule Deer Behavior.” Great Basin Naturalist 47:105-9.

*Hesselton, W. T., and R. M. Hesselton (1982) “White-tailed Deer.” In J. A. Chapman and G. A. Feldhamer, eds., Wild Mammals of North America: Biology, Management, and Economics, pp. 878-901. Baltimore and London: Johns Hopkins University Press.

*Hirth, D. H. (1977) “Social Behavior of White-Tailed Deer in Relation to Habitat.” Wildlife Monographs 53:1-55.

Jacobson, H. A. (1994) “Reproduction.” In D. Gerlach, S. Atwater, and J. Schnell, eds., Deer, pp. 98-108. Mechanicsburg, Pa.: Stackpole Books.

Marchinton, R. L., and D. H. Hirth (1984) “Behavior.” in L. K. Halls, ed., White-tailed Deer: Ecology and Management, pp. 129-68. Harrisburg, Pa.: Stackpole Books; Washington, DC: Wildlife Management Institute.

Marchinton, R. L. and W. G. Moore (1971) “Auto-erotic Behavior in Male White-tailed Deer.” Journal of Mammalogy 52:616-17.

*Rue, L. L., III (1989) The Deer of North America. 2nd ed. Danbury, Conn.: Outdoor Life Books.

Sadleir, R. M. F. S. (1987) “Reproduction of Female Cervids.” In C. M. Wemer, ed., Biology and Management of the Cervidae, pp. 123-44. Washington, D.C.: Smithsonian Institution Press.

Salwasser, H., S. A. Holl, and G. A. Ashcraft (1978) “Fawn Production and Survivial in the North Kings River Deer Herd.” California Fish and Game 64:38-52.

*Taylor, D. O. N., J. W. Thomas, and R. G. Marburger (1964) “Abnormal Antler Growth Associated with Hypogonadism in White-tailed Deer of Texas.” American Journal of Veterinary Research 25:179-85.

*Thomas, J. W., R. M. Robinson, and R. G. Marburger (1970) Studies in Hypogonadism in White-tailed Deer of the Central Mineral Region of Texas. Texas Parks and Wildlife Department Technical Series no. 5. Austin: Texas Parks and Wildlife Department.

*———(1965) “Social Behavior in a White-tailed Deer Herd Containing Hypogonadal Males.” Journal of Mammalogy 46:314-27.

*———(1964) “Hypogonadism in White-tailed Deer in the Central Mineral Region of Texas.” In J. B. Trefethen, ed., Transactions of the North American Wildlife and Natural Resources Conference 29:225-36. Washington, D.C.: Wildlife Management Institute.

*Wishart, W. D. (1985) “Frequency of Antlered White-tailed Does in Camp Wainright, Alberta.” Journal of Mammalogy 35:486-88.

*Wislocki, G. B. (1956) “Further Notes on Antlers in Female Deer of the Genus Odocoileus.” Journal of Mammalogy 37:231-35.

*———(1954) “Antlers in Female Deer, With a Report on Three Cases in Odocoileus.” Journal of Mammalogy 35:486-95.

*Wong, B, and K. L. Parker (1988)“Estrus in Black-tailed Deer.” Journal of Mammalogy 69:168-71.

IDENTIFICATION: A large deer (standing 4-5 feet at the shoulder) with brownish red fur and a pale rump patch; males generally have enormous antlers and a long mane. DISTRIBUTION: Southern Canada, United States, northern Mexico; Eurasia, northwest Africa. HABITAT: Varied, including forests, meadows, chaparral, highlands. STUDY AREAS: Prairie Creek Redwoods State Park, California, subspecies C.e. roosevelti, the Roosevelt Elk; Isle of Rhum, Scotland, subspecies C.e. scoticus, the British Red Deer.