grasses of genera such as Panicum (especially Panicum turgidum) and Aristida, and browse plants such as Leptadenia species, Cassia italica, and Cornulaca monacantha. Reproduction Both males and females reach sexual maturity at 18-24 months of age. Births peak between March and October. Mating frequency is greater when environmental conditions are favorable. In zoos, males are sexually most active in autumn. The estrous cycle lasts roughly 24 days, and females experience an anovulatory period in spring. Periods between births are less than 332 days, showing that the scimitar oryx is polyestrous. Courting is done by means of a mating circle; the male and female stand parallel to one another, facing in opposite directions, and then circle around each other until the female allows the male to mount from behind. If the female is not ready to mate, she runs away and circles in the reverse direction. Pregnant females leave the herd for a week, give birth to the calf, and mate again during their postpartum estrus; thus, they can produce one calf a year. Gestation lasts about nine months, after which a single calf is born, weighing . Twin births are very rare - only 0.7% of the births observed in one study. Both mother and calf return to the main herd within hours of the birth. The female separates herself from the herd for a few hours while she nurses the calf. Weaning starts at 3.5 months, and the young become fully independent around 14 weeks old. Habitat and distribution The scimitar oryx once inhabited grassy steppes, semideserts and deserts in a narrow strip of central north Africa (Niger and Chad). It was reintroduced in Libya. It was widespread on the fringes of the Sahara, mainly in subdesert steppe, the grassy zone between the real desert and the Sahel, an area characterized by an annual rainfall of . In 1936, a single herd of 10,000 scimitar oryxes was seen in the steppe area of Chad. By the mid-1970s, Chad was home to more than 95% of the world population of this species. Status and conservation Following the Neolithic Subpluvial, around 7500 to 3500 BC, the "green Sahara" became dry and the scimitar oryx's population began to decline due to a loss of suitable habitat. This was further exacerbated by humans who hunted the scimitar oryx for both its meat and horns. The northern population was already almost lost before the