By Berke Altan
Geographic Range
Formerly occurred in desert and semidesert areas from Western Sahara and Mauritania to Egypt and Sudan. The current range reduced to desert regions in Northeastern Niger, North Central Chad, Northwestern Mali, Eastern Mauritania, Southern Libya, and Northwestern Sudan.
Habitat
The addax is not restricted to areas with free water, and is usually found within the desert or the surrounding stony country.
These animals are found in the following types of habitat:
temperate 
; terrestrial .
Terrestrial Biomes:
desert or dune ; savanna or grassland .
Physical Description
(132 to 275 lbs; avg. 203.5 lbs)
(59.06 to 66.93 in)
The addax is a sandy to almost white color during the summer, darkening to a grayish brown in the winter. White markings are present on the face, ears, belly, hips, and legs, and there is a black tuft of hair on the forehead. Horns are present on both males and females, average about 72 cm in length. They have approximately 1.5 to 3 spiral twists. The hooves are widely splayed as an adaption to travelling over desert sand. The addax head-body length is 150-170 cm, shoulder height is 95-115 cm, and tail length is 25-35 cm, with males being slightly larger than females.
Some key physical features:
endothermic ; homoiothermic; bilateral symmetry .
Sexual dimorphism: male larger, ornamentation .
Reproduction
Addax females give birth to as many as one young each year.
Breeding may occur at any time of the year, but is most common during the spring.
Breeding can occur throughout the year, with population birth peaks in winter and early spring. Gestation lasts 257-264 days, and there is almost always one young born. The calf is weaned after 23-39 weeks. Males are sexually mature at about 24 months, females during their second or third summer.
Key reproductive features:
iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous .
Lifespan/Longevity
Addaxes can live up to 25 years in captivity.
Behavior
The addax moves about the desert in herds of about 5-20 animals, and the herd is led by a dominant adult male. Males attempt to establish their own territory, trying to keep fertile females within these territories. A single male will mate with several females in his territory. Females establish a hierarchy of dominance, with the oldest animals ranking the highest. The addax is a "short leg" runner. It cannot achieve very high running speeds, allowing it to fall prey to faster predators.
Key behaviors:
cursorial; terricolous; diurnal ; motile ; territorial ; social ; dominance hierarchies .
Food Habits
The addax feeds on desert grasses and scrub. It searches great distances through the Sahara for sparse vegetation. The addax is the most desert-adapted of the antelopes. They spend most of their lives without drinking water; they receive enough moisture to survive from the vegetation they feed on.
Plant Foods:
leaves; wood, bark, or stems; flowers.
Economic Importance for Humans: Negative
None
Economic Importance for Humans: Positive
The meat and the skin of the addax are prized by local people, who use the hides for shoes and sandal soles.
Ways that people benefit from these animals:
food ; body parts are source of valuable material.
Conservation Status
IUCN Red List: [link]:
Critically Endangered.
US Federal List: [link]:
Endangered.
CITES: [link]:
Appendix I.
Addax are heavily built, slow running antelopes that are easy prey for humans with modern weapons. Hunting has decreased and eliminated many resident populations in many parts of its original range. Tourists in four-wheel-drive vehicles also affect the animals by chasing them until they die of exhaustion. Recent droughts, desertification of savanna lands, and increasing human population have all contributed to the decrease of addax populations.
Contributors
Berke Altan (author), University of Michigan.
Phil Myers (editor), Museum of Zoology, University of Michigan.
