White antelope, Screwhorn antelope
The addax (Addax nasomaculatus ), also known as the white antelope and the screwhorn antelope, is an antelope native to the Sahara Desert. The only member of the genus Addax, it was first described scientifically by Henri de Blainville in 1816. As suggested by its alternative name, the pale antelope has long, twisted horns – typically 55 to 80 cm (22 to 31 in) in females and 70 to 85 cm (28 to 33 in) in males. Males stand from 105 to 115 cm (41 to 45 in) at the shoulder, with females at 95 to 110 cm (37 to 43 in). They are sexually dimorphic, as the females are smaller than the males. The colour of the coat depends on the season – in the winter, it is greyish-brown with white hindquarters and legs, and long, brown hair on the head, neck, and shoulders; in the summer, the coat turns almost completely white or sandy blonde.
The addax mainly eats grasses and leaves of any available shrubs, leguminous herbs and bushes. They are well-adapted to exist in their desert habitat, as they can live without water for long periods of time. Addax form herds of five to 20 members, consisting of both males and females. They are led by the oldest female. Due to its slow movements, the addax is an easy target for its predators: humans, lions, leopards, cheetahs and African wild dogs. Breeding season is at its peak during winter and early spring. The natural habitat of the addax are arid regions, semideserts and sandy and stony deserts.
The addax is a critically endangered species of antelope, as classified by the IUCN. Although extremely rare in its native habitat due to unregulated hunting, it is quite common in captivity. The addax was once abundant in North Africa; however it is currently only native to Chad, Mauritania, and Niger. It is extirpated from Algeria, Egypt, Libya, Sudan, and Western Sahara, but has been reintroduced into Morocco and Tunisia.
The addax is an antelope of middle size, perfectly suited to living in harsh desert landscapes. A native of the Sahara Desert for thousands of years, it has thrived in regions where few other animals could survive. As with most other antelopes, males and females both have horns, which are slightly spiraled and can be more than a meter long. Their hooves are splayed so that they can travel on the sand. Their short, glossy coat is grey-brown in the winter, fading during the summer months to almost white. Out of the antelopes, the addax is the one most adapted to the desert. It drinks very little water, surviving on the moisture from the vegetation it eats.
Found across northern Africa in the past, on both the west and east sides of the Sahara, today addax populations exist in just a fragment of their former range in Chad, Niger, and possibly along the Mali - Mauritania border. These animals inhabit semi-deserts, arid regions, and stony and sandy deserts. They can occur in extremely arid regions that have less than 100 mm of rainfall per year. They also live in deserts where tussock grasses and the succulent thorn scrub cornulaca grow.
Addax are active mainly during the night, especially in the hot season; during the day, they will dig 'beds' under shade into the sand to avoid the desert sun’s heat and to shelter from sandstorms. Individual addax can live some distance from one another in their habitat without causing any problems because of their sensory skills whereby they can detect and find each other over huge distances. They are also able to track rainfall, heading for rainy areas where there is more vegetation. Some addax live with others in herds of 5-20 individuals of males and females. The herds usually stay in one place, though they may wonder when searching for food. The eldest dominant male usually leads the herd. Females establish a dominant hierarchy, the oldest animals having the highest ranking. Addax are known as "short leg" runners and cannot run very fast, so fall prey to predators who are faster.
Addax are herbivores (graminivores, folivores) and eat grasses and leaves of what shrubs, leguminous herbs, and bushes are available. They will also browse the leaves of Acacia trees in the absence of these grasses
Addax exhibit polygynous mating behavior. Males try to establish a territory of their own, attempting to keep breeding females inside the boundaries. A male will mate with a number of females in his territory. Year-round breeding occurs, with birth peaks in early spring and winter. Gestation lasts for 257-264 days, with one young being almost always the case. The calf is hidden for about the first 6 weeks and its mother suckles it 2-3 times each day. It is weaned at 23-39 weeks. Males are reproductively mature by about 24 months, and females at the time of the second or third summer.
Addax are slow-running, heavily built antelopes and so are easy prey for people with modern weapons. Many resident populations have been decreased or eliminated by hunting in many parts of this animal’s original range. Four-wheel-drive vehicles with tourists also affect addax by chasing them to the point of exhaustion and death. Recent droughts, increasing human population, and desertification of savanna lands have all contributed to decreasing addax populations.
According to the IUCN Red List, the total addax population size is around 30-90 mature individuals. Currently, this species is classified as Critically Endangered (CR) and its numbers today are decreasing.
