Fact Summary Taxonomy and Nomenclature Distribution and Habitat Physical Characteristics Behavior and Ecology Diet and Feeding Reproduction and Development Diseases and Pathology Managed Care Population and Conservation Status Web Resources Bibliography

Describer (Date): Equus asinus: Linneaus 1758. Syst. Nat., 10th edition, 1:73.
                           Equus africanus: Heuglin & Fitzinger 1866.

Kingdom: Animalia
    Phylum: Chordata
        Class: Mammalia
             Order: Perissodactyla (horses, tapirs, rhinos)
                Suborder: Hippomorpha (horse-like mammals)
                    Family: Equidae (wild and domestic horses, donkeys, kiang, onager, zebras, extinct quagga)
                           Genus: Equus
                                  Species: Equus asinus - domestic donkey (or burro, or ass)
                                  Species: Equus africanus - African Wild Ass
                                         Subspecies: Equus africanus africanus - Nubian Wild Ass - Critically Endangered
                                         Subspecies: Equus africanus somaliensis - Somali Wild Ass - Critically Endangered
                                  Species: Equus hemionus - Asian Wild ass or onager (plus 6 subspecies)
                                  Species: Equus kiang - Tibetan Wild Ass
                                  Species: Equus quagga - Extinct Quagga
                                  Species: Equus zebra - Mountain or Hartmann's Zebra
                                  Species: Equus grevyi - Grevy's Zebra
                                  Species: Equus burchelli - Plains or Burchelli's Zebra
                                  Species: Equus ferus - Wild horse
                                      Subspecies: Equus ferus Przewalskii - Prezwalski's Wild Horse
                                  Species: Equus caballus - domestic horse

• In 1995 Groves noted that there needs to be a way to classify domesticated animals when they are not natural taxa; this is a problem with naming donkeys and the wild asses from which they descend.
• In 2003 the International Commission on Zoological Nomenclature (the organization dedicated to "achieving stability and sense" in the scientific naming of animals) attempted to reduce confusion around naming of wild and domestic donkeys:
  • Wild donkeys could be referred to as Equus africanus, even if the domestic donkey's name had priority. (Bulletin of Zoological Nomenclature 2003)
  • Their ruling allows separate species names for wild (E. africanus) and domestic (E. asinus) forms of donkeys.
  • Many scientists give donkeys separate species status for convenience. (Corbet & Clutton-Brock 1984)
• All African wild asses may actually be a single population with variation by geographic area.
  • Resolving this question is important for conservation management plans (Moehlman 2002)
  • Somali wild asses may actually be the only surviving African wild ass; they may be a sister group to domestic donkeys. (Groves and Ryder 2000)
• Common Names:
  • Domestic donkey, burro, or ass.
  • African wild ass (two, possibly three subspecies: Somali, Nubian, and Abyssinian or Saharan wild asses) (Moehlman 2002)
                    

• Horses diverged from rhinos between 54 and 58 million years ago (Early Eocene). (Ryder 2009)
  • Horse lineages are called the hippomorphs; tapirs and rhinos are the ceratomorphs.
• Most likely horses first dispersed from Europe to North America at the beginning of the Eocene. (Hooker 2008)
  • Pliolophus is now considered the earliest horse; it is closely related Hyracotherium. (Froehlich 2002) (Hooker 2008)
• The horse family Equidae has three main divisions based on anatomy and DNA studies. (Oakenfull et al 2000)
  • The caballines - include domestic horse and Equus przewalskii, a wild ancestor (Forstén 1988)
  • The asses - include domestic donkey, African wild asses, and the hemionines (Asiatic onager and kiang)
  • Zebra
• The genus Equus is first identified at 3.7 million years ago. (Oakenfull et al 2000)
• The earliest known true African wild ass (E. africanus ) dates to 1.5 to 1.7 million years ago in Olduvai Gorge, Kenya. (Churcher 1982)
  • Domestic donkeys are descended from African wild asses (Clutton-Brock 1999)
  • Donkeys and closely related Asiatic asses have a long separate evolutionary history. (Forstén 1988,1989)
• Recent genetic study of horse fossil DNA suggests that in North America there may be only two lineages of horses between 500,000 and 13,000 years ago (Weinstock et al 2005)
  • The "stilt-legged" lineage were small horses with slender legs built like modern onagers and kiang of Asia (but the African wild asses, not Asian asses, are considered the ancestors of modern donkey). (Beja-Pereira 2004)
  • The caballine lineage horses resembled modern horses and the nearly extinct Przewalskii horses
  • Both lineages disappeared from North America by 13,000 years ago
• According to archaeological finds, donkeys (burros) were domesticated about 5,000 years ago. (Rossel et al 2008)
  • Ten nearly complete donkey (E. asinus) skeletons carefully buried in tombs in Abydos, Egypt showed evidence of load-bearing and thus suggested that they had been domesticated. (Rossel et al 2008)
• DNA analysis reveals that more than one distinct wild population of asses contributed genes to today's domestic donkey. (Beja-Pereira et al 2004)
  • Donkeys may be the only hoofed animal domesticated exclusively in Africa.
    • African domestication happened during time when humans struggled to cope with development of the Sahara Desert some 5,000 to 7,000 years ago.
  • Groves (1986), however, suggests original donkey domestication might be in the Middle East.

• Populations of wild asses (E. africanus) originally in North Africa from Morocco to Somalia and perhaps western Asia (Clutton-Brock 1981)
  • Found in wild today only in Ethiopia, Eritrea, and Somalia (IUCN Red List 2008)
  • Uncertain in Egypt; Sudan (IUCN Red List 2008)
  • Occupy some 15,000 sq km (sq mi ) (IUCN Red List 2008)
• Domesticated and escaped feral donkeys are found world-wide.
  • Large feral populations in western Australia, estimated at 1.5 million in 1983. (Nowak 1999)
  • Populations in Death Valley (California and Nevada) nearly eliminated by BLM
  • 36,000 wild horses and burros in 10 western U.S. states. (http://www.blm.gov/wo/st/en/prog/wild_horse_and_burro.html
  • Donkey populations, world-wide, especially in Africa, Asia, Latin America are increasing (Starkey & Starkey

• Marginal desert land; adapted to areas that are arid at least seasonally. (Forstén 1988)
• African Wild Asses live in arid and semi-arid bush/shrub land, grassland, and desert (IUCN 2008 Red List)
  • Inhabit the volcanic and stony Great Rift Valley of Eritrea and Ethiopia from below sea level to 2,000 m (6552 ft)
  • Desert habitat in Eritrea and Ethiopia suffers from severe frequent droughts.

Body Weight: 275 kg (606 lb)
Head/Body Length: 200 cm (6.6 ft)
Tail Length: 42 cm (17 in)
Shoulder Height: 125 -145 cm (4.2-5.5 ft)

Note: Domestic breeds vary in height at shoulder: 80-150 cm (2.6-4.9 ft)

General

• Equus asinus (donkeys). A small, short- legged equid with exceptionally long ears.
• Equus africanus somaliensis (Somali wild asses) have dark barring on legs; patterns vary geographically.
• 40-42 teeth (6 upper incisors, 6 lower; 2 canines upper jaw, 2 lower; 6 or 8 premolars upper jaw, 6 lower; 6 molars upper jaw, 6 lower))
  • Simpler molar tooth pattern for donkeys and asses compared to caballine horses. (Bennett 1980)

• Short, smooth gray or brown coat with dark stripe down center of back; stripe may not be continuous
• Underside lighter; legs may have bands.
• No white on rump. (Grinder et al 2006) 

•  Very little sexual dimorphism

• Donkeys have 62 chromosomes (domestic horses have 64)
• Hooves are the narrowest of any equid and quite small; these animals are very sure-footed as a result
• Mane is upright, long, and thin; no forelock
• Tail is tufted.
• Donkey ears 200 mm (7.9 in) or longer (Grinder et al 2006)
• Somali wild asses ears 187-200 mm (7.3-7.6 in) (Groves & Ryder 2000)
• Adaptations to extreme heat in desert environments include ability to raise body temperature by as much as 6.5 ° C (11.7 F°) (Moehlman 1998)

•  Wild stallions may occupy a territory only in order to mate with females that enter the space; herds dissolve each evening. (Klingel 1990)
  • Stallion marks territory with dung heaps.
• Feral domestic donkeys have the same behaviors in North American deserts as in African wild asses: in more lush habitats, permanent territorial groups are established with one or more stallions and mares. (Klingel 1990)
• Feral domestic donkeys studied in Arizona had a mean annual home range of 19.2 sq.km ( 7.4 sq.mi)
• African Wild Asses have a territory averaging about 23 sq. km (8.9 sq. mi) (Klingel 1990)
  • This territory is unusually large for a hoofed animal; no biological explanation is known for this behavior. (Klingel 1998)

• Wild asses show different social organization depending on the environment. (Moehlman 1998)
  • In arid habitats: the only stable groups are a female and her recent foal - seen in Death Valley wild burros
  • In moderately wet (mesic) habitats, they form longer-term stable harem groups of bonded females and one or more adult males.
• No permanent bonds between Equus africanus adults; live in arid habitats small unstable groups of variable composition. (Klingel 1998) (Moehlman 2002)
  • Klingel (1998) observed young up to 3 years with adult mares and stallions.
  • Larger groups might have more than one stallion.
  • Two herds observed in the 1970's in Ethiopia had 43 and 49 asses, each with 11 stallions
• In desert habitats, stallions tolerate other males in their territory, but prevent access to the mares. (Klingel 1990)

• Stallions defending a territory are dominant but tolerate subordinate males. (Nowak 1999)
• No dominance order among adults - all are of equal rank. (Klingel 1998)
• No regular leader for migrations; any adult donkey, male or female can lead. (Klingel 1998)

•  Wild asses are territorial in their mating habits; the stallion attempts to keep other stallions away from mares within its territory. (Klingel 1990)
• Males attempt to control access to a critical resource - water - in order to have access to females. (Groves 2002)

• Territorial stallions chase or escort intruding males away from the mares (Klingel 1998)
• Mares and stallions defend young from intruders and herd mates. (McDonnell 2003)
• Levels of aggressive behavior were lower and mutual grooming more common in the feral donkeys that occupied habitats with ample resources; donkeys in desert habitats were more aggressive and groomed each other less often. (Moehlman 1998)

• As in all horses, foals engage in many play behaviors (McDonnell 2002,2003)
  • Toy with interesting objects in their environment: pick up, carry, sniff, chew, shake, pull, or paw items
  • Mount other young or adults
  • Frolic, run, chase, buck, jump, leap
  • Engage in King of the Mountain competitions and play fighting
  • Moehlman (1998) observed more play in foals living in a resource-rich environment on a Georgia barrier island than ones living in Death Valley, California.

•  A territorial stallion shows dominance by postures (McDonnell 2003)
  • Upright stance
  • Forward facing ears,
  • Ritual chasing of other stallions
  • Examination of other individuals' scents

• Females call males during estrus
• Grunts and growls are antagonistic
• Whuffles communicate position to others
• Snorts indicate alarm
• Calls termed brays (hee-haws) travel long distances
  • Donkey brays are unique: are made when breathing in ("hee") and breathing out ("haw"). (Browning & Scheifele 2001)

• Stallions examine nasal and genital areas of other asses for scent information.  
• Dung heaps left by territorial stallions do not ward off intruders (Klingel 1998)
  • Purpose seems to be to help the stallion recognize his own territory.

• Wild individuals have been clocked at 50 km/hr.
• Most common modes of locomotion are symmetrical walk or trot and an asymmetrical gallop
• Also canter, jump, trek, stampede, and swim.

•  Feral donkeys may outcompete mountain sheep in many ranges. (Groves 1974)

• Donkeys are ungulates with browsing and grazing habits.
• Consume grasses, bark, leaves, even creosote bushes in desert areas. (Groves 1974)
• A small herd of introduced donkeys was observed in 1998-2001 in Belgium's coastal dunes (Lamoot et al 2004)
  • Preferred grassy parts of the habitat over shrub or woodland parts
  • Consumed 80% grasses, sedges, rushes; 10 % other flowering herbaceous plants; 10% woody plants
• Can survive with little water and can tolerate even salty water. (Klingel 1990)
  • In wild, Equus africanus individuals sometimes go for 2-3 days without water. (Groves 1974)
  • Have more endurance and tolerate reduced food and water better than other horse species. (Klingel 1990)
• Young foals and nursing females need to be near water for daily drinks. (Moehlman 2002)
• Donkeys and other asses have evolved to use sparse fibrous vegetation and have more efficient digestion than horses; their digestion is similar in efficiency to that of goats.(Choshniak et al 1989)
• In arid Death Valley, female donkeys with young stay within 1.6 km (1 mi) of water sources. (Moehlman 1998)
• In arid Death Valley feral donkeys spend significantly more time eating than did donkeys in habitats with more resources like a Georgia coastal island. (Moehlman 1998)
  • Donkeys were browsers in the desert and grazers on the lusher island.

• In arid climates, donkeys and African wild ass stallions control access to resources females require (like water) and thus gain access to females in estrus; Grevy's zebras have similar mating systems (Moehlman 1998)
• In wetter habitats, donkey stallions have a harem of bonded females that he defends from outside males; horses and plains zebras also have this mating system (Moehlman 1998)
• Feral donkey mares in estrus outside a stallion's territory of may attract a number of stallions who fight but may all mate with her. (Klingel 1998)
• Receptive females stand with hind legs apart and tail held to the side. (Klingel 1998)
• Mating sequence: (Klingel 1998)
  • Stallions sniff the female
  • Female kicks towards him in a ritualized fashion and travels forward.
  • Stallion follows, driving her for an average distance of 20 m (65.6ft).
    • Tame and feral donkeys and onager males all drive or chase the females a certain distance before mating
  • When female halts, male mounts, and copulates.

• Females may be in estrus up to 8 days. (Grinder et al 2006)
• Feral donkeys and African wild ass females in a group do not all come into estrus at the same time (Moehlman 1998)
• Peak breeding seasons may vary in feral populations according to timing of wet/dry seasons. (Grinder et al 2006)

• One or two foals born
• Weight: 25 kg (55 lb)

• Can begin nibbling plants at 5 days when incisor teeth erupt (Moehlman 1998)
• Regularly browse on vegetation by 2 weeks but depend on mother's milk for fluid. (Moelhman 1998)
• Weaned at 12-14 months (Grinder et al 2006)
• At one year foal still spends most of its time no more than 10 m (32.8 ft) away from mother. (Grinder et al 2006)

• Sexual maturity for males by 2 years; can produce sperm earlier. (Grinder et al 2006)
• Females reach sexual maturity at 1.5 yrs. but don't usually breed until 2-3 yrs (Grinder et al 2006)
  • Observed wild donkeys in U. S. deserts and reported females have first foals later, at age 3.5 to 4 years (Moehlman 2002)

• Averages 20 years in wild (Klingel 1990)
• Domestic donkey/burro 47 years (Nowak 1999)

• Feral donkeys in U.S. face mountain lion and wolf predators
• Feral donkeys in U.S. subject to Wild, Free-Roaming Horse and Burro Act of 1971 (Grinder et al 2006)
  • Law requires protection, management, and control of horses and burros on public lands
  • National Park Service is exempt from this law and may remove burros dead or alive from its lands.
• Wild donkeys in Australia are culled by hunters in helicopters and on the ground.

• Donkeys suffer many of the same illnesses and pathologies as horses with some exceptions.
  • Several diseases of the donkey occur due to their longevity, including chronic lung disease.
  • Younger donkeys may suffer more infectious lung diseases than older ones.
  • Donkeys suffer from equine herpesrvirus 1 (EHV-1) and 4 as do horses, but they also may have three varieties of Asine herpesvirus (AHV)
  • Donkeys may suffer from equine influenza as do horses, but donkeys show more marked symptoms and mortality is higher.
    • Vaccinations are effective and important aspects of good care.
• Donkeys can be infected with a nematode that infect the lungs (Dictyocaulus arnfieldi).
• Domestic donkeys may become an intermediate host for tapeworms (Echinococcus granulosum) from carnivores that have defecated in donkey pastures.
  • Tapeworms cysts develop in the donkey lung or liver
  • Best control for this disease: treating dogs and cats for tapeworms
• Many lung diseases, including pneumonia, are not noticed in donkeys as easily as in horses because donkeys are more sedentary and don't cough as much.
  • When symptoms are obvious, the disease may be quite advanced; lung disease is a common cause of death
• Many pathologies seen in donkeys, modern and from the archaeological record, come from their use in carrying loads and transporting people.
  • Evidence of significant skeletal damage from excess weight-bearing in donkeys discovered buried in Egyptian tombs. (Rossel et al 2008)

• Captive Breeding
  • African pastoralists often breed their donkeys to wild asses. (Clutton-Brock 1999)
    • This breeding pattern may impact the genetics of the wild ass populations. (Moehlman 2002)
  • A cross between a male donkey and female horse: a mule (can be either sex)
  • A cross between a female donkey and a male horse: a hinny (can be either sex)
  • Both crosses usually, but not always, infertile. (Yang et al 2004)
  • Head and front end of the crosses resemble the male (sire) and the hindquarters look more like the female (dam); a hybrid mule's head, therefore, resembles the sire's large donkey head. (Clutton-Brock 1981)
  • A male zebra/female donkey cross makes a zebroid, zebrass, or ze-donky (American Donkey and Mule Society website 2009)
  • A rare female zebra/male donkey cross yields a zebrinny (American Donkey and Mule Society website 2009)
•  All species of horses can interbreed, but don't do so normally in the wild. (Clutton-Brock 1999)
• World-wide, donkeys are mainly used for carrying loads but they also have other uses, including: (Starkey & Starkey 1997)
  • Some cultures prize donkeys as indicators of wealth or status
  • Some people eat donkey meat
  • Donkeys can be milked
  • Donkeys guard sheep and other livestock
  • Donkeys in industrialized countries may be companions, used for breeding and showing, kept as pack animals or for riding

• 1598: Spanish explorer Juan de Onate brought horses and probably donkeys to U.S. Southwest. (Grinder et al 2006)
• 1599: First wild donkeys recorded in U.S. (Grinder et al 2006)
• Late 1800's: Donkeys imported to Western Australia for transportation and labor before railroads established.
• Total number of observed African Wild Asses (Equus africanus) in Ethiopia and Eritrea is 70. A rough estimate of a total population is 600. (IUCN Red List 2008)
  • Of this total number, only 23 mature individuals are recorded with a maximum number around 200 individuals.
  • In Ethiopia, the Yangudi-Rassa National Park (4,731 km²) and the Mille-Serdo Wild Ass Reserve (8,766 km²) were established in 1969. (IUCN Red List 2008)
  • In Eritrea, the government designated the African Wild Ass area between the Buri Peninsula and the Dalool Depression as a high-priority area for protection as a nature reserve. (IUCN Red List 2008)
  • No protected areas in Somalia. Some populations managed in captivity. (IUCN Red List 2008)
• 1986: 57 African Wild Asses in captivity
• 1999: 94 African Wild Asses in captivity
• 1971: Feral donkeys in U.S. subject to Wild, Free-Roaming Horse and Burro Act of 1971 (Grinder et al 2006)
  • Law requires protection, management, and control of horses and burros on public lands
  • National Park Service is exempt from this law and may remove burros dead or alive from its lands.
• Total number of donkeys (Equus asinus) estimated worldwide: 44 million and increasing. (Starkey & Starkey 1997)
  • Donkeys are valuable work animals for much of the world's poor and rural populations as well as industrializing nations that as yet do not have widespread access to motor vehicles for transportation. (Starkey & Starkey 1997)
• Total number of mules (a donkey/horse hybrid) worldwide estimated at 15 million (Starkey & Starkey 1997)
• ISIS captive population

• IUCN Status: Equus africanus is Critically Endangered C2a(i) ver. 3.1
  • Population trend: declining (IUCN Red List 2008)
• CITES Status: Equus africanus is listed in Appendix I

• Primary threat is hunting for food and medicinal purposes; others include:
• Agriculture and aquaculture
• Livestock farming and ranching
• Nomadic grazing
• Human disturbance, war, civil unrest, military exercises
• Invasive species
• Invasive non-native species
• Climate change and severe weather; droughts
• Breeding with domestic donkeys (Groves 2002)

• The Donkey Sanctuary: Website discusses issues regarding care and humane treatment of donkeys  
• The American Donkey and Mule Society: Website includes much information geared for the donkey enthusiasts who breed, show, and want to care for donkeys and mules.
• The National Wild Horse and Burro Program: Website of the U.S. Bureau of Land Management; includes information on how to adopt wild burros/donkeys.

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