|At the Cincinnati Zoo|
(F. Cuvier, 1842)
|Synonyms  |
The rhim gazelle or rhim from Arab Language غزال الريم in Arabic(Gazella leptoceros), also known as the slender-horned gazelle, African sand gazelle or Loder's gazelle, is a pale-coated gazelle with long slender horns and well adapted to desert life. It is considered an endangered species because fewer than 2500 are left in the wild. They are found in Algeria, Egypt, Tunisia  and Libya, and possibly Chad, Mali, Niger, and Sudan.
According to Richard Lydekker, the name rhim is known in Algeria and Libya, while in Tunisian and Egyptian the animal is known as the ghazal abiad, "white gazelle", owing to its pale coat. The name rhim is cognate with and perhaps derived from the Hebrew term re'em found in the Bible, which may refer to an aurochs, oryx or perhaps a unicorn. 
Although described and named by Frédéric Cuvier in 1842, the rhim gazelle was rediscovered by Edmund Giles Loder later in the same century, hence the synonym Gazella loderi and the common name Loder's gazelle. 
Growing to a length of 101 to 116 cm (40 to 46 in), this is the palest of the gazelles, and well adapted to desert life in many ways. The upper parts are pale buff or cream and the limbs and under parts white or pale buff. The horns on the male are slender and slightly S-shaped; those of the female are even thinner, lighter and nearly straight. There are faint facial markings and an indistinct stripe along the side. The tail is brownish-black, about 15 cm (6 in) long, and contrasts with the pale rump. 
The rhim gazelle is known from Algeria, Tunisia, Libya and Egypt. It has also been reported from Niger and Chad, but these sightings seem doubtful and its precise range is unclear. The rhim gazelle is found in isolated pockets across the central Sahara Desert. The extreme heat of this environment limits their feeding to the early morning and evening, and G. leptoceros gains most of its water requirements from dew and plant moisture, relying little on open water sources. The rhim gazelle is a nomadic species, moving across its desert range in search of vegetation, though it does not have a set migratory pattern. Its typical habitat is sand dunes and the depressions between them and other sandy areas, but also rocky areas. 
Rhim gazelles use a special type of temperature regulation called heterothermy to survive in this harsh desert climate. With 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. 
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". 
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. 
Oryx is a genus consisting of four large antelope species called oryxes. Their pelage is pale with contrasting dark markings in the face and on the legs, and their long horns are almost straight. The exception is the scimitar oryx, which lacks dark markings on the legs, only has faint dark markings on the head, has an ochre neck, and has horns that are clearly decurved.
The addax, 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 in females and 70 to 85 cm in males. Males stand from 105 to 115 cm at the shoulder, with females at 95 to 110 cm. 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 scimitar oryx, also known as the scimitar-horned oryx and the Sahara oryx, is a Oryx species that was once widespread across North Africa. In 2000, it was declared extinct in the wild on the IUCN Red List.
The dorcas gazelle, also known as the ariel gazelle, is a small and common gazelle. The dorcas gazelle stands about 55–65 cm at the shoulder, with a head and body length of 90–110 cm and a weight of 15–20 kg. The numerous subspecies survive on vegetation in grassland, steppe, wadis, mountain desert and in semidesert climates of Africa and Arabia. About 35,000–40,000 exist in the wild.
The Antilopines are even-toed ungulates belonging to the subfamily Antilopinae of the family Bovidae. The members of tribe Antilopini include the gazelles, blackbucks, springboks, gerenuks, dibatags, and Central Asian gazelles, are often referred to as true antelopes. True antelopes occur in much of Africa and Asia, with the highest concentration of species occurring in East Africa in Sudan, Eritrea, Ethiopia, Somalia, Kenya, and Tanzania. The saigas and Tibetan antelopes inhabit much of central and western Asia. The dwarf antelopes of tribe Neotragini live entirely in sub-Saharan Africa.
The mountain gazelle, also called the True Gazelle, is a species of gazelle widely but unevenly distributed.
Cuvier's gazelle is a species of gazelle native to Algeria, Morocco, Western Sahara, and Tunisia. It is also known as the edmi. It is one of the darkest gazelle species, possibly an adaptation to its partial woodland habitat. It is sometimes placed into the genus Trachelocele together with the goitered gazelles and the rhim gazelles.
The North Saharan steppe and woodlands is a desert ecoregion, in the deserts and xeric shrublands biome, that forms the northern edge of the Sahara. It extends east and west across Northern Africa, south of the Mediterranean dry woodlands and steppe ecoregion of the Maghreb and Cyrenaica, which is part of the Mediterranean forests, woodlands, and scrub biome. Winter rains sustain shrublands and dry woodlands that form an ecotone between the Mediterranean climate regions to the north and the hyper-arid Sahara Desert ecoregion to the south.
The Tibesti-Jebel Uweinat montane xeric woodlands is a deserts and xeric shrublands ecoregion in the eastern Sahara. The woodlands ecoregion occupies two separate highland regions, covering portions of northern Chad, southwestern Egypt, southern Libya, and northwestern Sudan.
The Termit Massif Total Reserve is a nature reserve in the southeast of Niger which was established in January 1962. In March 2012, a national nature and cultural reserve was established covering an area of 100,000 square kilometres (39,000 sq mi), including the entire area of the Termit Massif and Tin Toumma desert, making it the largest single protected area in Africa. The area provides habitat for many critically endangered species. Prominent among them is the addax antelope, which is categorized under the IUCN Red List as one of the rarest and most endangered species in the world; about 300 of them are reported in the reserve. A conservation effort has been launched by the Government of Niger in collaboration with many international conservation agencies. The reserve has also been declared an UNESCO World Heritage Site for the biodiversity value of the Termit Massif and surrounding Sahara Desert and for the cultural value of its archaeological sites.
The Gadabedji Total Reserve is a nature reserve in the central region of Niger. It is a Total Faunal Reserve IUCN type IV, covering some 76,000 hectares within the northern tip of the Maradi Region, just north of the town of Dakoro, and south of the border with the Agadez Region. The reserve is also recognized biosphere reserve by the Unesco since 2017.
Jebil is a national park in Tunisia situated within the Sahara desert. Covering an area of 150,000 hectares, it is the country's second-largest national park, after Senghar-Jebbes National Park. Though large, it is relatively new having been designated a national park in 1994. Until Senghar-Jebbes was declared, it was the only national park within the Sahara desert proper.
Heuglin's gazelle, also known as the Eritrean gazelle, is a species of gazelle found east of the Nile River in Eritrea, Ethiopia and Sudan. It was considered a subspecies of the red-fronted gazelle or conspecific with Thomson's gazelle and Mongalla gazelle by some authors in the past. This small gazelle stands nearly 67 cm (26 in) at the shoulder and weighs between 15 and 35 kg. The coat is dark reddish brown with a dark reddish stripe on the flanks, except for the underparts and the rump which are white. Horns, present in both sexes, measure 15 to 35 cm in length.
The Arabian sand gazelle or reem is a species of gazelle native to the Middle East, specifically the Arabian and Syrian Deserts.