Eritrean gazelle (''Eudorcas tilonura'') is a species of

gazelle A gazelle is one of many antelope species in the genus ''Gazella'' . There are also seven species included in two further genera; '' Eudorcas'' and '' Nanger'', which were formerly considered subgenera of ''Gazella''. A third former subgenus, ' ...

found east of the

Nile River The Nile (also known as the Nile River or River Nile) is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa. It has historically been considered the longest river i ...

in Eritrea, Ethiopia and Sudan. It was considered a

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of the

red-fronted gazelle The red-fronted gazelle (''Eudorcas rufifrons'') is widely but unevenly distributed gazelle across the middle of Africa from Senegal to northeastern Ethiopia. It is mainly resident in the Sahel zone, a narrow cross-Africa band south of the Sahar ...

(''E. rufifrons'') or

conspecific Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species. Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organism ...

with

Thomson's gazelle Thomson's gazelle (''Eudorcas thomsonii'') is one of the best known species of gazelles. It is named after explorer Joseph Thomson (explorer), Joseph Thomson and is sometimes referred to as a "tommie". It is considered by some to be a subspecies o ...

(''E. thomsonii'') and Mongalla gazelle (''E. albonotata'') by some authors in the past. This small gazelle stands nearly at the shoulder and weighs between . The

coat A coat is typically an outer garment for the upper body, worn by any gender for warmth or fashion. Coats typically have long sleeves and are open down the front, and closing by means of buttons, zippers, hook-and-loop fasteners (AKA velcro), ...

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 in length. Little is known about the ecology and behaviour of Heuglin's gazelles; they typically remain solitary or form groups of two to four. Herbivores, these gazelles possibly browse as well as graze.

Gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregn ...

lasts nearly six months, after which probably a single calf is born. Heuglin's gazelles inhabit open areas such as

steppe In physical geography, a steppe () is an ecoregion characterized by grassland plains without closed forests except near rivers and lakes. Steppe biomes may include: * the montane grasslands and shrublands biome * the tropical and subtropica ...

s, dry grasslands and thorn bushlands up to an elevation of .

Habitat loss Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

and illegal hunting for meat are major threats to the survival of these gazelles. Populations might have fallen by 20% in roughly nine years after 2008; as of 2016, only 2,500 to 3,500 individuals remain in small fragmented groups, with fewer than 2,500 adults. Heuglin's gazelle is classified as

Endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

Taxonomy

German explorer and ornithologist Theodor von Heuglin first described Heuglin's gazelle in 1863. He based his description on a specimen from the plains close to Ain-Saba in Bogosland in Abyssinia (the Ethiopian Empire). This species has been considered a

of the

(''Eudorcas rufifrons'') or

with Thomson's gazelle (''E. thomsonii'') and Mongalla gazelle (''E. albonotata'') by some authors. In 2013, biologist Colin Groves considered Heuglin's gazelle an independent species, and this has subsequently been followed by many authors.

Characteristics

This species is notably smaller than other

s, shows significantly lesser

sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

and has shorter and thinner horns (present in both sexes). The head-and-body length is between , and the shoulder height is nearly . Males weigh between , while the weight of females varies from . The

is dark reddish brown, except for the underparts and the rump which are white. There is a dark reddish stripe on the flanks. The face is darker in the middle, and there are white circles around the eyes. The horns measure in males and in females, and turn inward at the tips. They are spaced apart at the base, and the tips are separated by . Females have more slender and straighter horns than do males. The tail measures and is

rufous Rufous () is a color that may be described as reddish-brown or brownish- red, as of rust or oxidised iron. The first recorded use of ''rufous'' as a color name in English was in 1782. However, the color is also recorded earlier in 1527 as a d ...

at the base, turning black towards the end. It is smaller and more rufous than the red-fronted gazelle, the nose is unmarked.

Dorcas gazelle The dorcas gazelle (''Gazella dorcas''), also known as the ariel gazelle, is a small and common gazelle. The dorcas gazelle stands about at the shoulder, with a head and body length of and a weight of . The numerous subspecies survive on veget ...

sympatric In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct spe ...

with Heuglin's gazelle in some areas, has a lighter reddish stripe. The larger and paler Soemmerring's gazelle shares its range with Heuglin's gazelle in southwestern Eritrea, and has short, heavy horns curved backward with tips pointing inward, a whiter rump and short white hairs on the tail.

Ecology and behaviour

Heuglin's gazelles lead solitary lives or form groups of two to four. They scrape the ground to create resting sites under shrubs or large trees, such as the Egyptian balsam (''Balanites aegyptiaca'') in

savanna A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) biome and ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach th ...

hs and '' Vachellia nubica'' in shrublands, during the hottest period of the day. Groups of gazelles may rest in shallower sites for long periods of time, as suggested by the increasing dung piles in these areas. Little is known of

territorial A territory is an area of land, sea, or space, belonging or connected to a particular country, person, or animal. In international politics, a territory is usually a geographic area which has not been granted the powers of self-government, ...

behaviour in the wild; captive males form dung heaps close to the fences of their enclosures, smelling and scratching the ground nearby followed by excretion.

Preorbital gland The preorbital gland is a paired exocrine gland found in many species of artiodactyls, which is homologous to the lacrimal gland found in humans. These glands are trenchlike slits of dark blue to black, nearly bare skin extending from the media ...

s are also used for marking. Herbivores, they possibly browse as well as graze. Though Heuglin's gazelles can survive for long periods without water, they are more water-dependent than other gazelles in their range. Copulation lasts a few seconds; the male stands upright on the hindfeet and mounts the female.

lasts 184 to 189 days, after which probably a single calf is born; most births take place in the wet season.

Jackal Jackals are Canidae, canids native to Africa and Eurasia. While the word has historically been used for many canines of the subtribe Canina (subtribe), canina, in modern use it most commonly refers to three species: the closely related black-b ...

s may prey on young; hyaenas may also be potential

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

s. Little else is known about the ecology and behaviour of these gazelles.

Distribution and habitat

The range is east of the

and patchy, bounded by the southern Red Sea Hills in Sudan and mountainous terrain in northwestern Ethiopia and western Eritrea. Heuglin's gazelles inhabit open areas such as

s, dry grasslands and thorn bushlands up to an elevation of . Little is known about the populations and their status. Numbers have plummeted in Eritrea; in 2019 the Forestry and Wild Life Authority of Eritrea declared that Heuglin's gazelle had been sighted again in the country in the Dige sub-zone ( Gash-Barka Region). The gazelle was reportedly seen last during the time of the Italian colonial rule in Eritrea (19th to 20th centuries).

Threats and conservation

The

classifies Heuglin's gazelle as

. According to the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

, the numbers might have fallen by as much as 20% in roughly nine years after 2008. As of 2016, only 2,500 to 3,500 individuals remain in small fragmented groups, with fewer than 2,500 adults. The gazelle is suffering from severe

habitat loss Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

due to

overgrazing Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature ...

deforestation Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...

agricultural expansion Agricultural expansion describes the growth of agricultural land ( arable land, pastures, etc.) especially in the 20th and 21st centuries. The agricultural expansion is often explained as a direct consequence of the global increase in food and e ...

and

drought A drought is a period of drier-than-normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, ...

s. Illegal hunting for meat is another major threat. Heuglin's gazelle occurs in several protected areas: Gash-Setit in Eritrea, Kafta Sheraro National Park (and probably Alatash National Park) in Ethiopia, and Dinder National Park in Sudan. Antelope conservationist Rod East noted that populations in the Dinder National Park are threatened by hunting particularly in the wet season when the animals often cross the border of the park. Moreover, in the dry season camel and goat herders often trespass the area and let their animals graze on the vegetation, depriving Heuglin's gazelles of food and resting sites.

References

{{Taxonbar, from1=Q27980418, from2=Q9266323 Heuglin's gazelle Mammals of Eritrea Mammals of Ethiopia Mammals of Sudan Heuglin's gazelle Taxa named by Theodor von Heuglin