The Addax (Addax nasomaculatus), also known as the screwhorn antelope, is a critically endangered desert antelope that lives in several isolated regions in the Sahara desert. This species of the antelope family is closely related to the oryx, but differs from other antelopes by having large square teeth like cattle and lacking the typical facial glands. Although extremely rare in its native habitat, it is quite common in captivity and is regularly bred on ranches where they are hunted as trophies. There are fewer than 500 addax left in wild, with fewer than 860 in captivity.
The Addax stands about 1 meter tall at the shoulder and its weight varies from 60 to 120 kilograms. The coloring of their coat varies with the season. In the winter it is greyish brown with white hind quarters and legs. In the summer, the coat turns almost completely white or sandy blonde. Their head is marked with brown or black patches that form an X over their nose. They have a scraggly beard and prominent red nostrils. Long black hairs stick out between their curved and spiraling horns ending in a short mane on the neck. Horns, found on both males and females, have two to three twists and can reach 80 centimetres in females and 120 centimetres in males. Their tail is short and slender, ending in a puff of hair. The hooves are broad with flat soles and strong dewclaws to help them walk on soft sand.
In ancient times, addax spread from Northern Africa through Arabia and the Levant. Pictures from Egyptian tombs show them being kept as domesticated animals in around 2500 BC. More recently, addax were found from Algeria to Sudan but due to several reasons, they have become much more restricted and rare. The population became critically endangered from both destruction of their habitat for commercial projects and hunting for horns or use as leather. Since the addax are slow by comparison with other antelopes, and are known to ride themselves to death, they have been an easy target for mounted hunters.
Addax live in desert terrain where they eat grass, and leaves of what shrub and bushes are available. They are amply suited to live in the deep desert under extreme conditions. Addax can survive without free water almost indefinitely, because they get moisture from their food and dew that condenses on plants.Scientists believe that the addax has a special lining in its stomach that stores water in pouches to use in times of dehydration.
Addax are nocturnal: they rest during the day in depressions they dig for themselves. Addax are able to live far apart, because their keen sensory powers allow them to locate each other at great distances.