The gemsbok is remarkably adapted to its arid environment; particularly noteworthy is its ability to survive without drinking water for most of the year (5). It conserves water within its body by lying in the shade during the hottest part of the day, and restricts activity to early mornings, late afternoons or the cool nights. The gemsbok does not waste precious moisture on panting or sweating, but instead allows its body temperature to rise by a few degrees above normal on hot days (5). Gemsboks are gregarious animals, usually found in herds of up to 30 individuals (2), but occasionally herds of several hundred animals can be encountered as they move to fresh grazing grounds (2). Gemsbok feed primarily on grass but when this is not available they will browse on shrubs, trees and herbs (6). During periods of drought, they obtain moisture from roots and tubers which are dug up with their hooves (6). From the age of five or six, male gemsboks establish territories. These territories are around 25 square kilometres and may be defended for up to three years (2). During this period, the male rounds up herds of females and young gemsbok into his territory to gain sole mating rights with receptive females (2). Single calves are born to females older than two years (5), after a pregnancy of around 264 days (6). The calf remains hidden during the day, but may venture out at night with the mother to a new site. At three to six weeks of age, the calf will join the herd (2). Gemsboks have a lifespan of around twenty years (6).