heterothermy, animals no longer keep their body temperature within a narrow range. Heterothermy in Rhim gazelles results in an increase in body temperature during the heat of the day that reduces the amount of evaporative cooling that gazelles would need to do in order to stay cool. By reducing evaporative cooling, gazelles reduce energy expenditure and conserve body water. During cooler temperatures at night, the stored heat can be released, allowing the gazelles’ body temperature to decrease back to a normal physiological range. Rhim gazelles maintain a normal skin temperature of about 35-°C in the summer and about 25-°C in the winter. When heterothermy is employed, the gazelle experiences a body temperature increase of 5-20°C depending on seasonal conditions. Status Endangered by the early 1970s, this species of gazelle was in serious decline. They were hunted firstly by mounted then by motorized hunters for sport, meat, or their horns, which were sold as ornaments in North African markets. The threats the animals face now include poaching, disturbance by humans and loss of suitable habitat. The International Union for Conservation of Nature estimates there may only be 300 to 600 mature individuals in the wild, and has rated their conservation status as "endangered". In philately On February 1, 1987, the Libyan General Posts and Telecommunications Company, in cooperation with World Wide Fund for Nature, issued a set of four postage stamps illustrating Gazella leptoceros. References Further reading External links ARKive - Images and movies of the rhim gazelle (Gazella leptoceros) Bizarre Survival Tactic: Gazelles Shrink Heart to Beat Heat Rhim gazelle's postal stamps on YouTube rhim gazelle Antelopes of North Africa Mammals of Chad Mammals of West Africa Fauna of the Sahara Fauna of Egypt Mammals of North Africa rhim gazelle rhim gazelle