All About Exotics

Oryx, Gemsbok

(Oryx gazella) Namibia and eastern South Africa. A close relative of the East African Oryx (Oryx beisa), which has 2 sub-species of its own, the East African Oryx “proper” (Oryx beisa beisa) and the Fringe-eared Oryx (Oryx beisa calliotis).

Introduction

In 1969 the New Mexico State Department of Game and Fish decided to introduce Gemsbok to the Tularosa Basin, more specifically, the White Sands Missile Range.  This introduction was a compromise between those who wanted to preserve nature and those who wanted to use it for recreation and hunting. From 1969 to 1977, 93 gemsbok were released.  The current population is estimated to be between 3,000 and 6,000 animals.  One major reason the gemsbok have thrived is the lack of natural predators.

ID

Gemsbok are light brownish-grey to tan in color, with lighter patches to the bottom rear of the rump. They have striking black and white facial markings that are unique to gemsbok and form a white “butterfly” pattern when viewed head on.  Their tails are long, tassle-like and black in color.  A dark brown stripe extends from the chin down the bottom edge of the neck through the join of the shoulder and leg along the lower flank of each side to the brown section of the rear leg. They have muscular necks and shoulders and their legs have white ’socks’ with a black patch on the front of both the front legs and both genders have long, straight, ringed horns. These horns average 33″ (reaching 4 feet) in length and are perfectly straight on males.  Their horns extend from the base of the skull to a slight outward and rearward angle.  Females have longer, thinner horns that have a slight outward and rearward curve in addition to their angle.  The only outward difference between males and females is their horns; hunters commonly mistake females for males. Gemsbok are one of the few antelope species where female trophies are sometimes more desirable than males.  Gemsbok stand around 4.5 ft at the shoulder; males can weigh between 450-500 lbs, while females weigh 350-400 lbs.  In instances of high productivity grazing, fat deposits under the skin become noticeable.

Behavior

Gemsbok live in herds of about 10-40 animals, which consist of a dominant male, a few non-dominant males, and females.  Aggressive displays are used by the males to establish the dominance hierarchy, and contact is usually minimal.  Gemsbok horns are used in both sidelong jabs and “fencing”.  As a result, distribution of animals in the herd is uniform, since gemsbok stand a horn’s length from each other.  They are highly nomadic in desert environments, but where ample water supplies exist, gemsbok may remain on smaller home ranges.  Mature bulls are territorial, defending core areas from non-dominant males.  They are masters at water conservation and body heat regulation.  When temperatures rise, their body temperatures rise until excess heat is shed via radiation.   Their bodies also possess mechanisms to ensure that the temperature of the blood circulating to the brain can stay below that of the body temperature.  When deprived of water, they do not sweat thus saving them from dehydration.  Gemsbok are able to increase their body temperature to 45 degrees from 35.7 degrees C in order to delay evaporative cooling (Buchart, 2003; Clark and Clark, 2005; Estes, 1991; Kingdon, 1997; Reed et al., 2003; Siyabona Africa Travel, 2005).  Its urine is highly concentrated and feces are almost dry, so that water loss is minimal.  Fast runners, the gemsbok can reach full speeds of up to 35 mph.

Food Habits

Oryx both graze and browse, preferring to feed on desert grasses.  In the U.S. the feed on tumbleweed, mesquite bean pods, yucca, buffalo gourds, grasses, roots and bulbs. Also utilize wild melons and cucumbers which provide a source of water. One major reason gemsbok introduction into the U.S. has been so successful is their ability to survive with little or no free-standing water.  They can utilize nearly every molecule of water stored in the plants that they consume.  Grazing at night allows the gemsbok to extract moisture when plant water content is highest.  Gemsbok may exhibit osteoplagia, or “bone eating”, to replenish phosphorus and calcium in their vegeatrian diets (see video below).  This behavior usually occurs following winter months.

Video: Gemsbok Eating Bone

Breeding

Gemsbok are polygynous. The dominant bull of the herd mates with receptive females.  Females reach sexual maturity by age 2.  Gestation lasts 9 to 10 months.  In Africa, gemsbok calving is seasonal and based on annual rainfall.  For gemsbok in the U.S. breeding appears to occur year round, producing one calf per year. Calves grow quickly and are weaned from their mothers in only 3.5 months.  Females are able to conceive 3 to 4 weeks after calves are weaned.

Life Span

18 years in the wild; 20 years in captivity.

Keeping gemsbok

Gemsbok are considered aggressive.  Mothers may attack other animals if defending her calf.  Hybridize with other oryx readily and hybrids are often fertile.  Can interbreed with addax antelope, said to produce a hybrid that is white with straight horns.  hand-rearing young can increase risk of attacks on humans.  It is advised to keep only one large, prime bull if males are kept together.  Keeping groups of males and females together can lend to higher reproduction and survival rates, but may also lead to broken horns as a result of increased fighting.  Advised to avoid stressing during periods of hot weather, as chased oryx may collapse and even die.  8 to 10 foot fence is often adequate for keeping gemsbok.

Hunting

Expect to pay anywhere from $3500 to $7500 for a gemsbok oryx in the U.S. – the average cost of a trophy gembok is ~ $5700.

Scoring

SCI Record Book Minimums (Kalahari Gemsbok)

	Standard	Bow
Bronze Score	81	72
Silver Score	90	83
Gold Score	93 7/8	87 7/8

Current SCI all-time record:  111 & 5/8 – W.J. Ray Jr. (pictured)

Note: SCI recognizes 2 “introduced” sub-species of East African Oryx – the Beisa Oryx and the Fringe-eared Oryx, but not the “introduced” Gemsbok Oryx.

Score Your Trophy

Orxy SCI Score Sheet

**To find an official measurer in your area, visit the Safari Club International’s (SCI) measurer locator