The scimitar oryx (Oryx dammah), also called the scimitar-horned oryx and the Sahara oryx, is a type of antelope that once lived widely across North Africa and parts of West and Central Africa. In 2000, it was listed as extinct in the wild on the IUCN Red List. However, in 2023, its status was changed to endangered because a small group of the species has been reintroduced to Chad. This animal is adapted to survive in hot, dry desert environments and can go months or even years without drinking water. As a grazer, it gets most of the water it needs from the plants it eats.
The population of scimitar oryx declined over time due to changes in climate during the Neolithic period and later because people hunted them for their horns. Today, the species is raised in protected areas in Tunisia, Morocco, and Senegal, as well as on private exotic animal farms in the Texas Hill Country of the United States. In 2016, a program to reintroduce the species began, and a small herd now lives in Chad.
The scimitar oryx was the symbol of the ancient Egyptian Oryx nome and is currently the animal emblem of the Sahara Conservation Fund.
Taxonomy and naming
The scimitar oryx is part of the genus Oryx and the family Bovidae. A German naturalist named Lorenz Oken first described the animal in 1816, giving it the scientific name Oryx algazel. Over time, scientists have used many different names for the species, including Oryx tao, O. leucoryx, O. damma, O. dammah, O. bezoarticus, and O. ensicornis. In 1826, a scientist named Philipp Jakob Cretzschmar used the name Oryx ammah for the species. The next year, Oryx leucoryx was used, but this name was later found to be the same as the name for the Arabian oryx (Oryx beatrix), so Oryx algazel was used again. More than 100 years later, in 1951, scientists John Ellerman and Terence Morrison-Scott discovered that Oryx algazel could not be used as the official name. In January 1956, an international group called the International Trust for Zoological Nomenclature decided that Oryx dammah would be the correct scientific name. This name has not changed since then, even though some scientific papers published after 1956 used other names, such as O. gazella tao.
The scientific name Oryx dammah comes from the Ancient Greek word orux, meaning a gazelle or antelope (originally meaning a pickaxe), the Latin word damma, meaning a type of deer or antelope, and the Arabic word dammar, meaning a sheep. The scimitar oryx is named for its horns, which look like scimitars. Its common name in English is "scimitar-horned oryx" or simply "scimitar oryx."
Genetics and evolution
The scimitar oryx has 58 chromosomes, including one pair of large autosomes with a specific shape and 27 pairs of autosomes with a different shape. The X and Y chromosomes are the largest and smallest among these. A study published in 2007 found differences in the genetic makeup of scimitar oryx populations in Europe, North America, and other captive groups. Scientists think these differences in mitochondrial DNA groups began between 2.1 and 2.7 million years ago. Population numbers rose around 1.2 and 0.5 million years ago.
In another study, scientists compared the chromosome structures of several oryx species and subspecies—O. gazella, O. b. beisa, O. b. callotis, O. dammah, and O. leucoryx—with the standard chromosome structure of cattle (Bos taurus). All these species had 58 autosomes. The X and Y chromosomes remained the same across all five species.
Physical description
The scimitar oryx is a straight-horned antelope that stands just over 1 meter (3.3 feet) tall at the shoulder. Males weigh between 140 and 210 kilograms (310 to 460 pounds), while females weigh between 91 and 140 kilograms (201 to 309 pounds). The body length, from the head to the base of the tail, ranges from 140 to 240 centimeters (55 to 94 inches). The tail is 45 to 60 centimeters (18 to 24 inches) long and ends with a tuft. Males are larger than females.
The oryx has a white coat with a red-brown chest and black markings on the forehead and along the nose. The white coat reflects sunlight, and the black areas and the tip of the tongue help protect against sunburn. The white color also helps reduce heat in the desert. Baby oryx are born with yellow coats and no markings, which develop later. Their fur changes to adult coloring between 3 and 12 months of age.
Both males and females have horns. Female horns are more slender than male horns. The horns are long, thin, and curved backward, a unique feature of this species. They measure 1.0 to 1.2 meters (3 feet 3 inches to 3 feet 11 inches) in length for both sexes. The inside of the horns is very thin, making them easy to break. Female oryx have four teats on their udders. Their large, wide hooves are adapted for walking on sandy desert ground. A scimitar oryx can live up to 20 years. At the Smithsonian National Zoo, a female oryx lived to be 21 years old, which is longer than the typical lifespan of 15 years for females.
Diseases and parasites
The scimitar oryx can become sick with cryptosporidiosis, a disease caused by tiny parasites in the Cryptosporidium group. These parasites belong to a larger group called Apicomplexa. A study in 2004 found that a type of parasite called C. parvum or similar organisms infected 155 different mammal species, including the scimitar oryx. In 2005, scientists discovered Cryptosporidium parasites in the feces of 100 mammals, including the scimitar oryx. Tiny parasite eggs from a new type of parasite, Eimeria oryxae, were found in the feces of a scimitar oryx at Zoo Garden in Riyadh. In France, scientists found a bacteria called Streptococcus uberis in an oryx for the first time. This bacteria caused an infection in the heart of the animal, which led to a serious condition called congestive heart failure and the animal’s death.
Ecology and behavior
The scimitar oryx lived in groups of two to 40 animals, usually led by a strong male. These animals once formed large groups of thousands during migration. In the wet season, they moved north into the Sahara desert. Scimitar oryxes are active during the day. In the cool mornings and evenings, they rest under trees or shrubs. If these are not available, they dig shallow holes in the ground with their hooves to rest. Male oryxes often fight, but these fights are short and not violent. Predators like lions, leopards, hyenas, cheetahs, jackals, vultures, and hunting dogs typically hunt weak or young oryxes.
Scimitar oryxes have a body system that works well in hot environments. They need less water because their bodies can release heat without using much water, allowing them to go long periods without drinking. Their body temperature can rise to nearly 46.5 °C (115.7 °F) before they start sweating. When water is plentiful, they can lower their body temperature below 36 °C (97 °F) at night by losing fluids through urination and feces, which helps them avoid reaching maximum body temperature the next day. These animals can survive extremely high temperatures that would harm most mammals. They have a network of tiny blood vessels that carries blood from the heart to the brain, passing near the nose, which cools the blood by up to 3 °C (5 °F) before it reaches the brain, a sensitive organ to heat.
In the wild, scimitar oryxes live in steppe and desert areas. They eat plants like grass, herbs, shrubs, succulents, legumes, roots, buds, and fruit. They can survive without water for 9-10 months because their kidneys reduce water loss through urination, an adaptation to desert life. They get water from plants such as wild melon (Citrullus colocynthis), Indigofera oblongifolia, and the leafless twigs of Capparis decidua. At night or in the early morning, they search for plants like Indigofera colutea, which produce a moisture-absorbing substance that provides water. They eat tuft grasses like Cymbopogon schoenanthus after rains but prefer more flavorful grasses such as Cenchrus biflorus, Panicum laetum, and Dactyloctenium aegyptium. During dry seasons, they eat seedpods of Acacia raddiana and rely on perennial grasses like Panicum turgidum and Aristida, as well as browse plants like Leptadenia species, Cassia italica, and Cornulaca monacantha.
Both males and females become sexually mature at 18-24 months. Births occur most often between March and October. Mating happens more frequently when conditions are good. In zoos, males are most active during autumn. The reproductive cycle lasts about 24 days, and females do not ovulate in spring. The time between births is less than 332 days, showing that scimitar oryxes can mate multiple times a year.
Mating involves a circle dance. The male and female stand facing opposite directions, then circle each other until the female allows the male to mount her from behind. If the female is not ready, she runs away and circles in the opposite direction. Mating lasts about 10 seconds. Females can mate again shortly after giving birth, allowing them to have one calf each year. Pregnancy lasts about nine months, after which a single calf is born, weighing 10–15 kg (22–33 lb). Twin births are very rare, occurring in only 0.7% of observed births. After birth, the mother joins the herd while the calf stays hidden. The female separates from the herd for a few hours to nurse and clean the calf as it defecates. Weaning begins at 3.5 months, and young oryxes become independent around 14 weeks old.
Habitat and distribution
The scimitar oryx lived in grassy steppes, half deserts, and deserts in a small area of central northern Africa, especially in Niger and Chad. These animals were common along the edges of the Sahara Desert, mainly in a grassland area between the true desert and the Sahel. This region receives about 75–150 mm (3.0–5.9 in) of rain each year. In 1936, a group of 10,000 scimitar oryxes was observed in the steppe area of Chad. By the mid-1970s, Chad had more than 95% of the world’s population of this species.
Status and conservation
After the Neolithic Subpluvial, which occurred around 7500 to 3500 BC, the "green Sahara" became dry, and the scimitar oryx population started to decrease because their habitat became unsuitable. This decline was made worse by humans who hunted the scimitar oryx for meat and horns. By the 20th century, the northern population was nearly gone. During the 20th century, the use of horses and firearms by nomadic hunters caused further population loss. The southern population declined faster when Europeans settled the area and hunted the oryx for meat, hides, and horns. French involvement in World War II and a civil war in Chad starting in the 1960s likely caused more hunting for food. Roadkill, nomadic settlements near watering holes (where oryx feed during dry seasons), and the introduction of cattle and firearms for hunting also reduced their numbers.
The IUCN, an organization that studies wildlife, lists the scimitar oryx as no longer found in the wild in Algeria, Burkina Faso, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Nigeria, Senegal, Sudan, Tunisia, and Western Sahara. It has also declared the species extinct in the wild since 2000. Reports of scimitar oryx sightings in Chad and Niger have not been confirmed, even after surveys from 2001 to 2004. At least 500 oryx were estimated to survive in Chad and Niger until 1985, but by 1988, only a few remained in the wild.
A global program now exists to breed scimitar oryx in captivity. In 2015, about 1,750 oryx were part of breeding programs. At the program’s peak, up to 11,000 oryx were kept in Texas farms, and 4,000 were in Arab states in the Persian Gulf. Reintroduction plans include fenced herds in Bou-Hedma National Park (1985), Sidi Toui National Park (1999), and Oued Dekouk National Park (1999) in Tunisia; Souss-Massa National Park (1995) in Morocco; and Ferlo Faunal Reserve (1998) and Guembeul Wildlife Reserve (1999) in Senegal.
Chad is leading a project to reintroduce the species in Ouadi Rimé-Ouadi Achim Game Reserve with help from the Sahara Conservation Fund and the Environment Agency of Abu Dhabi. This reserve covers 78,000 square kilometers, about the size of Scotland. In 2016, the first group of 21 oryx was released into an acclimation enclosure and later fully released in the wild. By early 2017, this group had produced a calf, the first wild birth in over 20 years. A second group of six males and eight females was added to the enclosure in January 2017. In 2016, a captive-bred group was placed in an enclosure in the reserve and later released. In 2017, 21 more oryx were added to the enclosure. The first group released in 2016 adapted well to their environment. In 2017, a herd of 75 oryx was reintroduced by Chad’s Ministry of Environment and Fisheries and the Sahara Conservation Fund. By 2021, 60 new calves were born, bringing the total number of oryx in the wild to about 400.
The Marwell Zoo in Hampshire and the Edinburgh Zoo have worked with ZSL (Zoological Society of London) to reintroduce captive-bred oryx to their natural habitats. Tunisian reintroductions began in 1985 with 10 oryx from the Marwell and Edinburgh Zoos (organized by ZSL). In 1999 and 2007, Marwell helped release oryx into three more protected areas within their former range.
In culture
In ancient Egypt, scimitar oryxes were kept as pets or used for religious ceremonies or as food. They were called ran and raised in captivity. In ancient Rome, they were kept in enclosed areas and used for hunting games, and wealthy Romans ate them. The scimitar oryx was the main prey for hunters in the Sahelo-Saharan region. Its skin is considered valuable, and the king of Rio de Oro sent 1,000 shields made from its hide to a friend during the Middle Ages. Later, its hide was used to make ropes, harnesses, and saddles.
The idea of the one-horned unicorn may have come from seeing injured scimitar oryxes. Aristotle and Pliny the Elder believed the oryx was the original model for the unicorn. When viewed from certain angles, the oryx may appear to have one horn instead of two. Since its horns are made of hollow bone that cannot grow back, if a scimitar oryx lost one horn, it would have only one for the rest of its life.
In 2015, a scimitar oryx named Yellow Nose, who lives in Portland, Oregon, escaped from his home and scared hikers in Forest Park. The next day, he was found and returned to his enclosure.