African wild ass | |
---|---|
Somali wild ass subspecies (Equus africanus somaliensis) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Perissodactyla |
Family: | Equidae |
Genus: | Equus |
Subgenus: | Asinus |
Species: | E. africanus |
Binomial name | |
Equus africanus | |
Subspecies | |
E. a. africanus Contents | |
Geographic range |
The African wild ass (Equus africanus) or African wild donkey is a wild member of the horse family, Equidae. [3] This species is thought to be the ancestor of the domestic donkey (Equus asinus), which is sometimes placed within the same species. [4] They live in the deserts and other arid areas of the Horn of Africa, in Eritrea, Ethiopia and Somalia. It formerly had a wider range north and west into Sudan, Egypt, and Libya. It is Critically Endangered, with about 570 existing in the wild.
The African wild ass is about 1.2 metres (4 ft) tall and weighs approximately 250 kilograms (600 lb). [5] The short, smooth coat is a light grey to fawn colour, fading quickly to white on the undersides and legs. There is a slender, dark dorsal stripe in all subspecies, while in the Nubian wild ass (E. a. africanus), as well as the domestic donkey, there is a stripe across the shoulder. [6] The legs of the Somali wild ass (E. a. somaliensis) are horizontally striped with black, resembling those of a zebra. [5] On the nape of the neck, there is a stiff, upright mane, the hairs of which are tipped with black.[ citation needed ] The ears are large with black margins. The tail terminates with a black brush. The hooves are slender and approximately of the diameter as the legs. [5]
The genus Equus, which includes all extant equines, is believed to have evolved from Dinohippus , via the intermediate form Plesippus . One of the oldest species is Equus simplicidens , described as zebra-like with a donkey-shaped head. The oldest fossil to date is ~3.5 million years old from Idaho in the United States. The genus appears to have spread quickly into the Old World, with the similarly aged Equus livenzovensis documented from western Europe and Russia. [7]
Molecular phylogenies indicate the most recent common ancestor of all modern equids (members of the genus Equus) lived ~5.6 (3.9–7.8) mya. Direct paleogenomic sequencing of a 700,000-year-old middle Pleistocene horse metapodial bone from Canada implies a more recent 4.07 Myr before present date for the most recent common ancestor (MRCA) within the range of 4.0 to 4.5 Myr BP. [8] The oldest divergencies are the Asian hemiones (subgenus E. (Asinus), including the kulan, onager, and kiang), followed by the African zebras (subgenera E. (Dolichohippus), and E. (Hippotigris)). All other modern forms including the domesticated horse (and many fossil Pliocene and Pleistocene forms) belong to the subgenus E. (Equus) which diverged ~4.8 (3.2–6.5) million years ago. [9]
Different authors consider the African wild ass and the domesticated donkey one or two species; either view is technically legitimate, though the former is phylogenetically more accurate.[ citation needed ] However, the American Society of Mammalogists classifies the donkey as a distinct species, as it does with almost all domestic mammals. [10]
The species name for the African wild ass is sometimes given as asinus, from the domestic donkey, whose specific name is older and usually would have priority. But this usage is erroneous since the International Commission on Zoological Nomenclature has conserved the name Equus africanus in Opinion 2027. This was done to prevent the confusing situation of the phylogenetic ancestor being taxonomically included in its descendant.
Thus, if one species is recognized, the correct scientific name of the donkey is E. africanus asinus.
The first published name for the African wild ass, Asinus africanus, Fitzinger, 1858, is a nomen nudum . [11] The name Equus taeniopus von Heuglin, 1861 [12] is rejected as indeterminable, as it is based on an animal that cannot be identified and may have been a hybrid between a domestic donkey and a Somali wild ass; the type has not been preserved. [11] The first available name thus becomes Asinus africanus von Heuglin & Fitzinger, 1866. [2] [11] A lectotype is designated: a skull of an adult female collected by von Heuglin near Atbarah River, Sudan, and present in the State Museum of Natural History Stuttgart, MNS 32026. [11] The three subspecies recognized:
Image | Subspecies | Distribution |
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Nubian wild ass Equus africanus africanus (von Heuglin & Fitzinger, 1866) [2] | Nubian Desert of northeastern Sudan, from east of the Nile River to the Red Sea and south to the Atbarah River and northern Eritrea | |
Somali wild ass Equus africanus somaliensis (Noack, 1884) [11] [13] | Somalia, Somaliland, Eritrea and Ethiopia | |
†Atlas wild ass Equus africanus atlanticus (P. Thomas, 1884) | Region around the Atlas Mountains, across modern day Algeria, Tunisia and Morocco |
African wild asses are well suited to life in a desert or semidesert environment. [5] They have tough digestive systems, which can break down desert vegetation and extract moisture from food efficiently. They can also go without water for a fairly long time. Their large ears give them an excellent sense of hearing and help in cooling.[ citation needed ] Because of the sparse vegetation in their environment wild asses live somewhat separated from each other (except for mothers and young), unlike the tightly grouped herds of wild horses. [1] They have very loud voices, which can be heard for over 3 km (1.9 mi), which helps them to keep in contact with other asses over the wide spaces of the desert.
The African wild ass is primarily active in the cooler hours between late afternoon and early morning, seeking shade and shelter amongst the rocky hills during the day. The Somali wild ass is also very agile and nimble-footed, capable of moving quickly across boulder fields and in the mountains. On the flat, it has been recorded reaching speeds of 70 km/h (43 mph). In keeping with these feats, its soles are particularly hard and its hooves grow very quickly. [14]
Mature males defend large territories around 23 square kilometres in size, marking them with dung heaps – an essential marker in the flat, monotonous terrain. Due to the size of these ranges, the dominant male cannot exclude other males. Rather, intruders are tolerated – recognized and treated as subordinates, and kept as far away as possible from any of the resident females. In the presence of estrous females, the males bray loudly. These animals live in loose herds of up to fifty individuals.
In the wild, African wild ass breeding occurs during the wet season. [15] The gestation period lasts for 11 to 12 months, and one foal is born during the period from October to February. [15] [16] The foal weans for 6 to 8 months after birth, reaching sexual maturity at the age of 2 years. [16] Lifespan is up to 40 years in captivity. [15] [16]
Wild asses can run swiftly, almost as fast as a horse. However, unlike most hoofed mammals, their tendency is to not flee right away from a potentially dangerous situation, but to investigate first before deciding what to do. When they need to, they can defend themselves with kicks from both their front and hind legs. Equids were used in ancient Sumer to pull wagons circa 2600 BC, and then chariots on the Standard of Ur, circa 2000 BC. These have been suggested to represent onagers, but are now thought to have been domesticated asses. [17]
The African wild asses' diet consists of grasses, bark, and leaves. Despite being primarily adapted for living in an arid climate, they are dependent on water, and when not receiving the needed moisture from vegetation, they must drink at least once every three days. However, they can survive on a surprisingly small amount of liquid, and have been reported to drink salty or brackish water.
Though the species itself is under no threat of extinction, due to abundant domestic stock (donkeys and burros), the two extant wild subspecies are both listed as critically endangered. African wild asses have been captured for domestication for centuries and this, along with interbreeding between wild and domestic animals, has caused a distinct decline in population numbers. There are now only a few hundred individuals left in the wild. [4] These animals are also hunted for food and for traditional medicine in both Ethiopia and Somalia. [1] Competition with domestic livestock for grazing, and restricted access to water supplies caused by agricultural developments, pose further threats to the survival of this species. [1] The African wild ass is legally protected in the countries where it is currently found, although these measures often prove difficult to enforce. A protected population of the Somali wild ass exists in the Yotvata Hai-Bar Nature Reserve in Israel, to the north of Eilat. This reserve was established in 1968 with the view to bolster populations of endangered desert species. Populations of horses and asses are fairly resilient and, if the species is properly protected, it may well recover from its current low.
There are about 150 individual Somali wild asses living in zoos around the globe, of which 36 were born at Zoo Basel, [18] where this species' breeding program started with Basel's first Somali wild asses in 1970 and the first birth in 1972. [19]
Zoo Basel manages the European studbook for the Somali wild ass and coordinates the European Endangered Species Programme (EEP). [20] All European wild donkeys are either descendants of the original group at Zoo Basel or of 12 others that came from the Yotvata Hai-Bar Nature Reserve in Israel in 1972.
Equidae is the taxonomic family of horses and related animals, including the extant horses, asses, and zebras, and many other species known only from fossils. The family evolved around 50 million years ago from a small, multi-toed ungulate into larger, single-toed animals. All extant species are in the genus Equus, which originated in North America. Equidae belongs to the order Perissodactyla, which includes the extant tapirs and rhinoceros, and several extinct families.
How and when horses became domesticated has been disputed. Although horses appeared in Paleolithic cave art as early as 30,000 BC, these were wild horses and were probably hunted for meat. The clearest evidence of early use of the horse as a means of transport is from chariot burials dated c. 2000 BC. However, an increasing amount of evidence began to support the hypothesis that horses were domesticated in the Eurasian Steppes in approximately 3500 BC. Discoveries in the context of the Botai culture had suggested that Botai settlements in the Akmola Province of Kazakhstan are the location of the earliest domestication of the horse. Warmouth et al. (2012) pointed to horses having been domesticated around 3000 BC in what is now Ukraine and Western Kazakhstan.
The donkey is a domesticated equine. It derives from the African wild ass, Equus africanus, and may be classified either as a subspecies thereof, Equus africanus asinus, or as a separate species, Equus asinus. It was domesticated in Africa some 5000–7000 years ago, and has been used mainly as a working animal since that time.
Przewalski's horse, also called the takhi, Mongolian wild horse or Dzungarian horse, is a rare and endangered horse originally native to the steppes of Central Asia. It is named after the Russian geographer and explorer Nikolay Przhevalsky. Once extinct in the wild, since the 1990s it has been reintroduced to its native habitat in Mongolia in the Khustain Nuruu National Park, Takhin Tal Nature Reserve, and Khomiin Tal, as well as several other locales in Central Asia and Eastern Europe.
The onager, also known as hemione or Asiatic wild ass, is a species of the family Equidae native to Asia. A member of the subgenus Asinus, the onager was described and given its binomial name by German zoologist Peter Simon Pallas in 1775. Six subspecies have been recognized, two of which are extinct.
A zebroid is the offspring of any cross between a zebra and any other equine to create a hybrid. In most cases, the sire is a zebra stallion. The offspring of a donkey sire and zebra dam, called a donkra, and the offspring of a horse sire and a zebra dam, called a hebra, do exist, but are rare and are usually sterile. Zebroids have been bred since the 19th century. Charles Darwin noted several zebra hybrids in his works.
Equus is a genus of mammals in the family Equidae, which includes horses, asses, and zebras. Within the Equidae, Equus is the only recognized extant genus, comprising seven living species. Like Equidae more broadly, Equus has numerous extinct species known only from fossils. The genus most likely originated in North America and spread quickly to the Old World. Equines are odd-toed ungulates with slender legs, long heads, relatively long necks, manes, and long tails. All species are herbivorous, and mostly grazers, with simpler digestive systems than ruminants but able to subsist on lower-quality vegetation.
The kiang is the largest of the Asinus subgenus. It is native to the Tibetan Plateau in Ladakh, northern Pakistan, Tajikistan, China and northern Nepal. It inhabits montane grasslands and shrublands. Other common names for this species include Tibetan wild ass, khyang and gorkhar.
Grévy's zebra, also known as the imperial zebra, is the largest living wild equid and the most threatened of the three species of zebra, the other two being the plains zebra and the mountain zebra. Named after Jules Grévy, it is found in parts of Kenya and Ethiopia. Superficially, Grévy's zebras' physical features can help to identify it from the other zebra species; their overall appearance is slightly closer to that of a mule, compared to the more "equine" (horse) appearance of the plains and mountain zebras. Compared to other zebra species, Grévy's are the tallest; they have mule-like, larger ears, and have the tightest stripes of all zebras. They have distinctively erect manes, and more slender snouts.
The wild asses (Asinus) are a subgenus of single toed grazing ungulates. Its species are:
The wild horse is a species of the genus Equus, which includes as subspecies the modern domesticated horse as well as the endangered Przewalski's horse. The European wild horse, also known as the tarpan, that went extinct in the late 19th or early 20th century has previously been treated as the nominate subspecies of wild horse, Equus ferus ferus, but more recent studies have cast doubt on whether tarpans were truly wild or if they actually were feral horses or hybrids.
The Somali wild ass is a subspecies of the African wild ass.
Grant's zebra is the smallest of the seven subspecies of the plains zebra. This subspecies represents the zebra form of the Serengeti-Mara ecosystem and others across central Africa.
Asinus is a subgenus of Equus that encompasses several subspecies of the Equidae commonly known as wild asses, characterized by long ears, a lean, straight-backed build, lack of a true withers, a coarse mane and tail, and a reputation for considerable toughness and endurance.
The Atlas wild ass, also known as Algerian wild ass, is a purported extinct subspecies of the African wild ass that was once found across North Africa and parts of the Sahara.
The evolution of the horse, a mammal of the family Equidae, occurred over a geologic time scale of 50 million years, transforming the small, dog-sized, forest-dwelling Eohippus into the modern horse. Paleozoologists have been able to piece together a more complete outline of the evolutionary lineage of the modern horse than of any other animal. Much of this evolution took place in North America, where horses originated but became extinct about 10,000 years ago, before being reintroduced in the 15th century.
Feral donkeys were first brought to Australia as pack animals to replace horses, which had succumbed to native poisonous plants. Now numbering 5 million, they have been declared a pest, owing to their damage to vegetation and erosion of soil. Culling is mainly carried out by marksmen in helicopters, and experiments are being made in fertility control.
The Nubian wild ass is the nominate subspecies of African wild ass, and one of the ancestors of the domestic donkey, which was domesticated about 6,000 years ago. It is presumed to be extinct, though two populations potentially survive on the Caribbean island of Bonaire and in Gebel Elba.
The breeding programs at Zoo Basel have had many highlights since the zoo's opening in 1874. These include the worldwide first zoo births of an Indian rhinoceros and greater flamingo hatch, as well as the first European gorilla birth. Due to Zoo Basel's successful breeding programs, it manages the international studbook for the Indian rhinoceros and the pygmy hippopotamus, as well as several European studbooks.
The Turkmenian kulan, also called Transcaspian wild ass, Turkmenistani onager or simply the kulan, is a subspecies of onager native to Central Asia. It was declared Endangered in 2016.
This article incorporates CC BY-3.0 text from the reference. [11]