Addax

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Addax
A big male Addax showing as the power of his horns.jpg
An addax in Morocco
CITES Appendix I (CITES) [2]
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Bovidae
Subfamily: Hippotraginae
Genus: Addax
Laurillard, 1841
Species:
A. nasomaculatus
Binomial name
Addax nasomaculatus
(Blainville, 1816) [3]
Addax nasomaculatus distribution (IUCN 2015).png
Distribution of addax (IUCN 2015)
  Extant (resident)
  Reintroduced
Synonyms
List [3] [4]
  • Addax addax Cretzschmar, 1826
  • Addax gibbosa Savi, 1828
  • Addax mytilopesHamilton-Smith, 1827
  • Addax suturosaOtto, 1825
  • Cerophorus nasomaculataBlainville, 1816
  • Antilope addaxCretzschmar, 1826
  • Antilope suturosaOtto, 1825
  • Antilope mytilopesHamilton-Smith, 1827
  • Oryx addaxHamilton-Smith, 1827
  • Oryx nasomaculatus J.E. Gray, 1843
Addax in Yotvata Hai-Bar Nature Reserve. Addax - IZE-106w.jpg
Addax in Yotvata Hai-Bar Nature Reserve.

The addax (Addax nasomaculatus), 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 (22 to 31 in) in females and 70 to 85 cm (28 to 33 in) in males. Males stand from 105 to 115 cm (41 to 45 in) at the shoulder, with females at 95 to 110 cm (37 to 43 in). 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.

Contents

The addax mainly eats grasses and leaves of any available shrubs, leguminous herbs and bushes. They are well-adapted to exist in their desert habitat, as they can live without water for long periods of time. Addax form herds of five to 20 members, consisting of both males and females. They are led by the oldest female. Due to its slow movements, the addax is an easy target for its predators: humans, lions, leopards, cheetahs and African wild dogs. Breeding season is at its peak during winter and early spring. The natural habitat of the addax are arid regions, semideserts and sandy and stony deserts.

The addax is a critically endangered species of antelope, as classified by the IUCN. Although extremely rare in its native habitat due to unregulated hunting, it is quite common in captivity. The addax was once abundant in North Africa; however it is currently only native to Chad, Mauritania, and Niger. It is extirpated from Algeria, Egypt, Libya, Sudan, and Western Sahara, but has been reintroduced into Morocco and Tunisia.

Taxonomy and naming

The scientific name of the addax is Addax nasomaculatus. This antelope was first described by French zoologist and anatomist Henri Blainville in 1816. It is placed in the monotypic genus Addax and the family Bovidae. [3] Henri Blainville observed syntypes in Bullock's Pantherion and the Museum of the Royal College of Surgeons. English naturalist Richard Lydekker stated their type locality to be probably Senegambia, though he did not have anything to support the claim. Finally, from a discussion in 1898, it became more probable that British hunters or collectors obtained the addax from the part of the Sahara in Tunisia. [3]

The generic name Addax is thought to be obtained from an Arabic word meaning a wild animal with crooked horns. [5] It is also thought to have originated from a Latin word. The name was first used in 1693. [6] The specific name nasomaculatus comes from the Latin words nasus (or the prefix naso-) meaning nose, and maculatus meaning spotted, referring to the spots and facial markings of the species. Bedouins use another name for the addax, the Arabic bakr (or bagr) al wahsh, which literally means "the cow of the wild". That name can be used to refer to other ungulates as well. [4] [5] The other common names of addax are "white antelope" and "screwhorn antelope". [7]

Genetics

The addax has 29 pairs of chromosomes. All chromosomes are acrocentric except for the first pair of autosomes, which are submetacentric. The X chromosome is the largest of the acrocentric chromosomes, and the Y chromosome is medium-sized. The short and long arms of the pair of submetacentric autosomes correspond respectively to the 27th and 1st chromosomes in cattle and goats. In a study, the banding patterns of chromosomes in addax were found to be similar to those in four other species of the subfamily Hippotraginae. [4] [8]

History and fossil record

In ancient times, the addax occurred from northern Africa through Arabia and the Levant. Pictures in a tomb, dating back to 2500 BCE, show at least the partial domestication of the addax by the ancient Egyptians. These pictures show addax and some other antelopes tied with ropes to stakes. The number of addax captured by a person were considered an indicator of his high social and economic position in the society. [7] The pygarg ("white-buttocked") beast mentioned in Deuteronomy 14:5 is believed[ by whom? ] to have been an addax. But today, excess poaching has resulted in the extinction of this species in Egypt since the 1960s. [9]

Addax fossils have been found in four sites of Egypt – a 7000 BCE fossil from the Great Sand Sea, a 5000–6000 BCE fossil from Djara, a 4000–7000 BCE fossil from Abu Ballas Stufenmland and a 5000 BCE fossil from Gilf Kebir. Apart from these, fossils have also been excavated from Mittleres Wadi Howar (6300 BCE fossil), and Pleistocene fossils from Grotte Neandertaliens, Jebel Irhoud and Parc d'Hydra. [4]

Physical description

Addax nasomaculatus.jpg
The coat colour in summer
AddaxSnow2010.jpg
The coat colour in winter

The addax is a spiral-horned antelope. Male addaxes stand from 105 to 115 cm (41 to 45 in) at the shoulder, with females at 95 to 110 cm (37 to 43 in). They are sexually dimorphic, as the females are smaller than the males. [10] The head and body length in both sexes is 120 to 130 cm (47 to 51 in), with a 25 to 35 cm (9.8 to 13.8 in) long tail. The weight of males varies from 100 to 125 kg (220 to 276 lb), and that of females from 60 to 90 kg (130 to 200 lb). [4]

The coloring of the addax's coat varies with 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. [4] Their head is marked with brown or black patches that form an 'X' over their noses. They have scraggly beards and prominent red nostrils. Long, black hairs stick out between their curved and spiralling horns, ending in a short mane on the neck. [11]

Addax-Jerusalem-Biblical-Zoo-IZE-611.jpg
A male with long horns

The horns, which are found on both males and females, have two to three twists and are typically 55 to 80 cm (22 to 31 in) in females and 70 to 85 cm (28 to 33 in) in males, although the maximum recorded length is 109.2 cm (43.0 in). [4] The lower and middle portions of the horns are marked with a series of 30 to 35 ring-shaped ridges. [4] The tail is short and slender, ending in a puff of black hair. The hooves are broad with flat soles and strong dewclaws to help them walk on soft sand. [11] All four feet possess scent glands. [4] The life span of the addax is up to 19 years in the wild, [5] which can be extended to 25 years under captivity. [4] [10]

The addax closely resembles the scimitar oryx, but can be distinguished by its horns and facial markings. While the addax is spiral-horned, the scimitar oryx has decurved 127 cm (50 in) long horns. The addax has a brown hair tuft extending from the base of its horns to between its eyes. A white patch, continuing from the brown hair, extends until the middle of the cheek. On the other hand, the scimitar oryx has a white forehead with only a notable brown marking: a brown lateral stripe across its eyes. [4] It differs from other antelopes by having large, square teeth like cattle and lacking the typical facial glands. [4]

Addaxes in Souss-Massa National Park, Morocco

Parasites

The addax is most prone to parasites in moist climatic conditions. [12] Addaxes have always been infected with nematodes in the Trichostrongyloidea and Strongyloidea superfamilies. [13] In an exotic ranch in Texas, an addax was found host to the nematodes Haemonchus contortus and Longistrongylus curvispiculum in its abomasum, [4] of which the former was dominant. [14]

Behavior and ecology

These animals are mainly nocturnal, particularly in summer. In the day, they dig into the sand in shady locations and rest in these depressions, which also protect them from sandstorms.[ citation needed ] Addax herds contain both males and females, and have from five to 20 members. They will generally stay in one place and only wander widely in search of food. The addax has a strong social structure, probably based on age, and herds are led by the oldest female. [4] Herds are more likely to be found along the northern edge of the tropical rain system during the summer and move north as winter falls. They are able to track rainfall and will head for these areas where vegetation is more plentiful. Males are territorial and guard females, [15] while the females establish their own dominance hierarchies. [16]

Due to its slow movements, the addax is an easy target for predators such as humans, lions, leopards, cheetahs and African wild dogs. Caracals, servals and hyenas attack calves. The addax is normally not aggressive, though individuals may charge if they are disturbed. [4]

Adaptations

Addaxes grazing in dry conditions Addax-1-Zachi-Evenor.jpg
Addaxes grazing in dry conditions

The addax is amply suited to live in the deep desert under extreme conditions. It can survive without free water almost indefinitely, because it gets moisture from its food and dew that condenses on plants. Scientists[ who? ] believe the addax has a special lining in its stomach that stores water in pouches to use in times of dehydration. It also produces highly concentrated urine to conserve water. [17] The pale colour of the coat reflects radiant heat, and the length and density of the coat helps in thermoregulation. In the day the addax huddles together in shaded areas, and on cool nights rests in sand hollows. These practices help in dissipation of body heat and saving water by cooling the body through evaporation. [4]

In a study, eight addaxes on a diet of grass hay ( Chloris gayana ) were studied to determine the retention time of food from the digestive tract. It was found that food retention time was long, taken as an adaptation to a diet including a high proportion of slow fermenting grasses; while the long fluid retention time could be interpreted to be due to water-saving mechanisms with low water turnover and a roomy rumen. [18]

Diet

An addax calf with its mother Addax mit kalb.jpg
An addax calf with its mother

The addax lives in desert terrain where it eats grasses and leaves of what shrubs, leguminous herbs and bushes are available. Primarily a grazer, its staple foods include Aristida , Panicum , and Stipagrostis , and it will only consume browse, such as leaves of Acacia trees in the absence of these grasses. [18] It also eats perennials which turn green and sprout at the slightest bit of humidity or rain. The addax eats only certain parts of the plant and tends to crop the Aristida grasses neatly to the same height. By contrast, when feeding on Panicum grass, the drier outer leaves are left alone while it eats the tender inner shoots and seeds. These seeds are important part of the addax's diet, being its main source of protein. [11]

Reproduction

Females are sexually mature at 2 to 3 years of age and males at about 2 years. Breeding occurs throughout the year, but it peaks during winter and early spring. In the northern Sahara, breeding peaks at the end of winter and the beginning of spring; in the southern Sahara, breeding peaks from September to October and from January to mid-April. Each estrus bout lasts for one or two days. [4]

In a study, the blood serum of female addaxes was analyzed through immunoassay to know about their luteal phase. Estrous cycle duration was of about 33 days. During pregnancy, ultrasonography showed the uterine horns as coiled. The maximum diameters of the ovarian follicle and the corpus luteum were 15 mm (0.59 in) and 27 mm (1.1 in). Each female underwent an anovulatory period lasting 39 to 131 days, during which there was no ovulation. Anovulation was rare in winter, which suggested the effect of seasons on the estrous cycle. [19]

Gestation period lasts 257–270 days (about nine months). Females may lie or stand during the delivery, during which one calf is born. A postpartum estrus occurs after two or three days. [20] The calf weighs 5 kg (11 lb) at birth and is weaned at 23–29 weeks old. [21]

Habitat and distribution

The addax inhabits arid regions, semideserts and sandy and stony deserts. [17] It even occurs in extremely arid areas, with less than 100 mm annual rainfall. [1] It also inhabits deserts with tussock grasses (Stipagrostis species) and succulent thorn scrub Cornulaca . [22] Formerly, the addax was widespread in the Sahelo-Saharan region of Africa, west of the Nile Valley and all countries sharing the Sahara Desert; but today the only known self-sustaining population is present in the Termit Massif Reserve (Niger). However, there are reports of sightings from the eastern Air Mountains (Niger) and Bodélé (Chad). Rare nomads may be seen in northern Niger, southern Algeria and Libya; and the addax is rumoured to be present along the Mali/Mauritania border, though there have been no confirmed sightings. [1] The addax was once abundant in North Africa, native to Chad, Mauritania and Niger. It is extinct in Algeria, Egypt, Libya, Sudan and the Western Sahara. It has been reintroduced into Morocco and Tunisia. [1]

Threats and conservation

An addax in a breeding program at the Jerusalem Biblical Zoo, Israel Addax-Jerusalem-Biblical-Zoo-IZE-481b.jpg
An addax in a breeding program at the Jerusalem Biblical Zoo, Israel

Declines in the population of the addax have been ongoing since the mid-1800s. [22] More recently, addaxes were found from Algeria to Sudan, but due mainly to overhunting, they have become much more restricted and rare. [1]

Addaxes are easy to hunt due to their slow movements. Roadkill, firearms for easy hunting and nomadic settlements near waterholes (their dry-season feeding places) have also decreased their numbers. [23] Moreover, their meat and leather are highly prized. Other threats include chronic droughts in the deserts, habitat destruction due to more human settlements and agriculture. Fewer than 500 individuals are thought to exist in the wild today, most of the animals being found between the Termit area of Niger, the Bodélé region of western Chad, [1] and the Aoukar in Mauritania. [24]

Today there are over 600 addaxes in Europe, Yotvata Hai-Bar Nature Reserve (Israel), Sabratha (Libya), Giza Zoo (Egypt), North America, Japan and Australia under captive breeding programmes. There are thousands more in private collections and ranches in the United States and the Middle East. Addaxes are legally protected in Morocco, Tunisia, and Algeria; hunting of all gazelles is forbidden in Libya and Egypt. Although enormous reserves, such as the Hoggar Mountains and Tasilli in Algeria, the Ténéré in Niger, the Ouadi Rimé-Ouadi Achim Faunal Reserve in Chad, and the newly established Wadi Howar National Park in Sudan, cover areas where the addax previously occurred, some do not keep addaxes at the present time because they lack the resources. The addax has been reintroduced into Bou-Hedma National Park (Tunisia) and Souss-Massa National Park (Morocco). Reintroductions in the wild are ongoing in Jebil National Park (Tunisia) and Grand Erg Oriental (the Sahara), and another is planned for Morocco. [1]

Related Research Articles

Antelope Term referring to an even-toed ruminant

The term antelope is used to refer to many species of even-toed ruminant that are indigenous to various regions in Africa and Eurasia.

Bovidae Family of mammals belonging to even-toed ungulates

The Bovidae comprise the biological family of cloven-hoofed, ruminant mammals that includes cattle, bison, buffalo, antelopes, and goat-antelopes. A member of this family is called a bovid. With 143 extant species and 300 known extinct species, the family Bovidae consists of eight major subfamilies apart from the disputed Peleinae and Pantholopinae. The family evolved 20 million years ago, in the early Miocene.

<i>Oryx</i> Genus of mammals

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.

Sahara Desert on the African continent

The Sahara is a desert on the African continent. With an area of 9,200,000 square kilometres (3,600,000 sq mi), it is the largest hot desert in the world and the third largest desert overall, smaller only than the deserts of Antarctica and the northern Arctic.

Common eland Second largest antelope in the world

The common eland, also known as the southern eland or eland antelope, is a savannah and plains antelope found in East and Southern Africa. It is a species of the family Bovidae and genus Taurotragus. An adult male is around 1.6 metres (5') tall at the shoulder and can weigh up to 942 kg (2,077 lb) with an average of 500–600 kg (1,100–1,300 lb), 340–445 kg (750–981 lb) for females). It is the second largest antelope in the world, being slightly smaller on average than the giant eland. It was scientifically described by Peter Simon Pallas in 1766.

Giant eland An open-forest and savanna antelope of the family Bovidae

The giant eland, also known as the Lord Derby eland, is an open-forest and savanna antelope. A species of the family Bovidae and genus Taurotragus, it was described in 1847 by John Edward Gray. The giant eland is the largest species of antelope, with a body length ranging from 220–290 cm (86.5–114 in). There are two subspecies: T. d. derbianus and T. d. gigas.

Sable antelope Species of mammal

The sable antelope is an antelope which inhabits wooded savanna in East and Southern Africa, from the south of Kenya to South Africa, with a separate population in Angola.

East African oryx Species of mammal

The East African oryx, also known as the beisa is a species of antelope from East Africa. It has two subspecies: the common beisa oryx found in steppe and semidesert throughout the Horn of Africa and north of the Tana River, and the fringe-eared oryx south of the Tana River in southern Kenya and parts of Tanzania. In the past, some taxonomists considered it a subspecies of the gemsbok, but they are genetically distinct; the diploid chromosome count is 56 for the beisa and 58 for the gemsbok. The species is listed as Endangered by the IUCN.

Scimitar oryx Species of oryx

The scimitar oryx, also known as the scimitar-horned oryx and the Sahara oryx, is a species of Oryx that was once widespread across North Africa. The species went extinct in the wild in 2000, but a group was released into an acclimation enclosure within the Ouadi Rimé-Ouadi Achim Faunal Reserve in 2016, then reintroduced back into the wild. An additional 21 animals were placed in the acclimation enclosure in 2017. In 2000, the species was declared extinct in the wild by the International Union for the Conservation of Nature (IUCN). The first ones to be relocated were released into the wild in 2016 and have adapted well to their surroundings. In 2017, another heard of 75 scimitar-horned oryxes arrived in an operation led by Chad's Ministry of Environment and Fisheries and the Sahara Conservation Fund. In 2021, 60 new calves were born, bringing the number in the wild to about 400. The species has not been assessed by the IUCN, though, since 2016, when the species was truly extinct in the wild, so it remains as extinct in the wild (EW). This particular oryx can survive for months or even years without drinking water. A grazing animal, it derives most of its daily moisture intake from plants.

Arabian oryx Species of antelope

The Arabian oryx or white oryx is a medium-sized antelope with a distinct shoulder bump, long, straight horns, and a tufted tail. It is a bovid, and the smallest member of the genus Oryx, native to desert and steppe areas of the Arabian Peninsula. The Arabian oryx was extinct in the wild by the early 1970s, but was saved in zoos and private reserves, and was reintroduced into the wild starting in 1980.

Hirola Species of antelope

The hirola, Hunter's hartebeest or Hunter's antelope, is a critically endangered antelope species found on the border between Kenya and Somalia. They were discovered by the big game hunter and zoologist H.C.V. Hunter in 1888, although the African peoples of the region knew of its existence even before this "discovery". It is the only living member of the genus Beatragus, though other species are known from the fossil record. The global hirola population is estimated at 300–500 animals and there are none in captivity. According to a document produced by the International Union for Conservation of Nature "the loss of the hirola would be the first extinction of a mammalian genus on mainland Africa in modern human history".

Hartebeest grassland antelope

The hartebeest, also known as kongoni, is an African antelope. It is the only member of the genus Alcelaphus. Eight subspecies have been described, including two sometimes considered to be independent species. A large antelope, the hartebeest stands just over 1 m (3.3 ft) at the shoulder, and has a typical head-and-body length of 200 to 250 cm. The weight ranges from 100 to 200 kg. It has a particularly elongated forehead and oddly shaped horns, short neck, and pointed ears. Its legs, which often have black markings, are unusually long. The coat is generally short and shiny. Coat colour varies by the subspecies, from the sandy brown of the western hartebeest to the chocolate brown of the Swayne's hartebeest. Both sexes of all subspecies have horns, with those of females being more slender. Horns can reach lengths of 45–70 cm (18–28 in). Apart from its long face, the large chest and the sharply sloping back differentiate the hartebeest from other antelopes.

Nile lechwe Species of antelope

The Nile lechwe or Mrs Gray's lechwe is an endangered species of antelope found in swamps and grasslands in Sudan and Ethiopia.

Rhim gazelle Species of mammal

The rhim gazelle or rhim, 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.

Barbary sheep Species of mammal

The Barbary sheep, also known as aoudad is a species of caprid native to rocky mountains in North Africa. Six subspecies have been described. Although it is rare in its native North Africa, it has been introduced to North America, southern Europe, and elsewhere. It is also known in the Berber language as waddan or arwi, and in former French territories as the moufflon.

Cuviers gazelle Species of mammal

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.

<i>Taurotragus</i> Genus of mammals

Taurotragus is a genus of large antelopes of the African savanna, commonly known as elands. It contains two species: the common eland T. oryx and the giant eland T. derbianus.

Tragelaphini Tribe of antelopes

The tribe Tragelaphini, or the spiral-horned antelopes, are bovines that are endemic to sub-Sahara Africa. These include the bushbuck, kudus, and the elands. The scientific name is in reference to the mythical creature the tragelaph, a Chimera with the body of a stag and the head of a goat. They are medium-to-large, tall, long-legged antelopes characterized by their iconic twisted horns and striking pelage coloration patterns.

South Saharan steppe and woodlands South Sahara desert ecoregion

The South Saharan steppe and woodlands, also known as the South Sahara desert, is a deserts and xeric shrublands ecoregion of northern Africa. This band is a transitional region between the Sahara's very arid center to the north, and the wetter Sahelian Acacia savanna ecoregion to the south. In pre-modern times, the grasslands were grazed by migratory gazelles and other ungulates after the rainfalls. More recently, over-grazing by domestic livestock have degraded the territory. Despite the name of the ecoregion, there are few 'woodlands' in the area; those that exist are generally acacia and shrubs along rivers and in wadis.

Tibesti–Jebel Uweinat montane xeric woodlands desert ecoregion in Africa

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.

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