Gemsbok, Beisa

Name

The name "gemsbok" in English is derived from Afrikaans gemsbok, which itself is derived from Dutch name of the male chamois, gemsbok, and further from German Gämse ("chamois"). Although some superficial similarities in appearance (especially in the facial pattern) are noticed, the chamois and the oryx are not closely related. The usual pronunciation in English is.

Description

Gemsbok are light brownish-grey to tan in colour, with lighter patches toward the bottom rear of the rump. Their tails are long and black in colour. A blackish stripe extends from the chin down the lower edge of the neck, through the juncture of the shoulder and leg along the lower flank of each side to the blackish 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 horns. Comparably, the East African oryx lacks a dark patch at the base of the tail, has less black on the legs (none on the hindlegs), and less black on the lower flanks. One very rare colour morph is the "golden oryx", in which the gemsbok's black markings are muted and appear to be golden.

Gemsbok are the largest species in the genus Oryx. They stand about 1.2 m (3.9 ft) at the shoulder. The body length can vary from 190 to 240 cm (75 to 94 in) and the tail measures 45 to 90 cm (18 to 35 in). Male gemsbok can weigh between 180 and 240 kg (400 and 530 lb), while females weigh 100–210 kg (220–460 lb).

Horns

Gemsbok are widely hunted for their spectacular horns that average 85 cm (33 in) in length. From a distance, the only outward difference between males and females is their horns, and many hunters mistake females for males each year. In males horns tend to be thicker with larger bases. Females have slightly longer, thinner horns.

Female gemsbok use their horns to defend themselves and their offspring from predators, while males primarily use their horns to defend their territories from other males.

Gemsbok are one of the few antelope species where female trophies are sometimes more desirable than male ones. A gemsbok horn can be fashioned into a natural trumpet and, according to some authorities, can be used as a shofar.

Ecology and biology

Gemsbok live in herds of about 10–40 animals, which consist of a dominant male, a few nondominant males, and females. They are mainly desert-dwelling and do not depend on drinking water to supply their physiological needs. They can reach running speeds of up to 60 km/h (37 mph).

Diet

The gemsbok is generally a grazer but changes to browsing during the dry season or when grass is sparse. It may dig up to a meter deep to find roots and tubers, supplementing its water intake by eating wild tsama melons and cucumbers, which can provide all the water required (3 liters per 100 kg bodyweight and day).

Reproduction

The gemsbok is polygynous, with one resident male mating with the receptive females in the herd. The male is known to secure exclusive mating access to the females by attempting to herd mixed or nursery herds onto his territory. The gemsbok has no specified breeding season, but the young in a given herd tend to be of a similar age due to reproductive synchrony between females. Pregnant females leave the herd before giving birth. The gestation period lasts 270 days and mothers give birth to 1-2 offspring. The calf remains hidden 6 weeks after birth, after which mother and calf rejoin the herd. The calf is weaned at 3.5 months, becomes independent at 4.5 month, and achieves sexual maturity at 1.5–2 years in both sexes.

Introduction to North America

In 1969, the New Mexico State Department of Game and Fish decided to introduce gemsbok to the Tularosa Basin in the United States. Ninety-three were released from 1969 to 1977, with the current population estimated to be around 3,000 specimens. They thrive because their natural predators, including the lion, are not present.