The Critically Endangered hirola is a grazing antelope that can be found feeding most intensively on the grassy plains in the early morning and evening, using its large molars to chew the coarse grass (2). Like many other mammals inhabiting the hot, dry plains of Africa, the hirola can go for long periods without drinking, and survives drought by storing fat and avoiding unnecessary energetic activity (2). Females and their young form groups of between 5 and 40 individuals (2), while the role of mature males depends on population density and ecological factors (3). In areas and times of abundant food, males are thought to defend territories, and mark the area boundaries with faeces and secretions from the facial glands (3). They then attempt to mate with females that come to feed in the territory (3). In other areas, males defend a group of females, firmly leading them into new feeding areas or herding them from the rear (3). When competing for females or defending their territories males can assume two fighting positions; they adopt an unusual kneeling position when fighting intensely, and a standing position when sparring (2). Hirolas mate mostly during the long rains in February and March (3), leading to a gestation that lasts about 240 days (5). Females separate from their group to give birth to a calf at the beginning of the short rains in October and November (2) (3). Newborn calves are vulnerable prey for jackals, dogs, hyenas, and large cats and eagles (2).