smelling the special scent-producing glands on his hind legs. Female Mule Deer also sometimes mount each other when in heat; in addition, some does court other females using a chasing sequence known as RUSH COURTSHIP. In this behavior (which also occurs in heterosexual contexts), they race toward another female, stopping abruptly and sometimes pawing the ground, pacing, leaping into the air while twisting their body, or running in circles or figure eights; this causes the other doe to become excited and aroused. Adult male White-tailed Deer frequently develop “companionships” or bonds with one (or occasionally two) other adult males in their buck groups; male companions are generally not related to each other. These strong attachments constitute the stable “core” of each buck group, and although male companions typically separate during the breeding season, they usually resume their bonds once mating is over.
An extraordinary form of transgendered deer occurs in some populations of White-tails. These animals, which are genetically male but actually combine characteristics of both males and females, are sometimes called VELVET-HORNS because their antlers are permanently covered with the special “velvet” skin that in most males is shed after the antlers have grown. Their antlers are usually only spikes (without the extensive branching of other males’ antlers) and they slope backward and sometimes have enlarged bases. Physically, velvet-horns often have body proportions and facial features more typical of does, while their testes are small and undeveloped (and in fact the animals are infertile). A similar type of transgender is found among Mule Deer, where the animals are known as CACTUS BUCKS owing to the distinctive shape of their antlers (which sometimes also have elaborate spikes, prongs, and asymmetrical growths). Velvet-horns usually form their own social groups of three to seven animals and live separately from both does and nontransgendered males. In fact, they are often harassed and attacked by other deer. Nontransgendered White-tails (both does and bucks of all ages, even fawns) threaten velvet-horns who try to approach them—forcing them to remain no less than ten feet away—while bucks may actively charge velvet- horns to drive them away. When threatened, velvet-horns flee without giving the standard alarm signals of other deer (stamping their feet, snorting or whistling, and raising their tails). Sometimes, groups of up to six bucks “gang up” on a velvet-horn, chasing and even violently attacking it by gashing its rump with their antlers. As a result, velvet-horns are extremely wary around other deer, venturing near feeding areas cautiously and always remaining in groups on the periphery, or else refusing to approach at all when other deer are present. Interestingly, velvet-horns are almost always in superior physical condition compared to nontransgendered males, precisely because they do not breed. The rutting season is extremely taxing on breeding bucks, who rarely eat and may lose up to a quarter of their body weight. In contrast, velvet-horns consistently have excellent body fat deposits and are in prime shape.
Two types of gender-mixing females also occur among White-tailed and Mule Deer, both bearing antlers (females in these species do not usually have antlers). In one type, the antlers are similar to those of velvet-horns: they are permanently covered in velvet, are never shed, and are either spikes or asymmetrically branching. Unlike velvet-horns, such females are usually fertile, mating heterosexually and becoming mothers. The other type is a more complete form of intersexuality: the antlers are hard and polished, more closely resemble those of males in their branching structure, and may even be shed seasonally. These individuals usually combine both male and female sexual traits, such as having the genitalia and/or reproductive organs of both sexes, or partial organs of each sex, or chromosomes of one sex combined with the genitalia of the other.
Nonreproductive and Alternative Heterosexualities
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.
*Anderson, A. E. (1981) “Morphological and Physiological Characteristics.” In O. C. Wallmo, ed,
*Baber, D. W. (1987) “Gross Antler Anomaly in a California Mule Deer: The ‘Cactus’ Buck.”
Brown, B. A. (1974) “Social Organization in Male Groups of White-tailed Deer.” In V. Geist and F. Walther, eds.,
*Cowan, I. McT. (1946) “Antlered Doe Mule Deer.”
*Crispens, C. G., Jr., and J. K. Doutt (1973) “Sex Chromatin in Antlered Female Deer.”
*Donaldson, J. C., and J. K. Doutt (1965) “Antlers in Female White-tailed Deer: A 4-Year Study.”
*Doutt, J. K., and J. C. Donaldson (1959) “An Antlered Doe With Possible Masculinizing Tumor.”
