The Critically Endangered hirola is a grazing antelope that can be found feeding most intensively on the grassy plains in the early morning and evening, using its large molars to chew the coarse grass (2). Like many other mammals inhabiting the hot, dry plains of Africa, the hirola can go for long periods without drinking, and survives drought by storing fat and avoiding unnecessary energetic activity (2). Females and their young form groups of between 5 and 40 individuals (2), while the role of mature males depends on population density and ecological factors (3). In areas and times of abundant food, males are thought to defend territories, and mark the area boundaries with faeces and secretions from the facial glands (3). They then attempt to mate with females that come to feed in the territory (3). In other areas, males defend a group of females, firmly leading them into new feeding areas or herding them from the rear (3). When competing for females or defending their territories males can assume two fighting positions; they adopt an unusual kneeling position when fighting intensely, and a standing position when sparring (2). Hirolas mate mostly during the long rains in February and March (3), leading to a gestation that lasts about 240 days (5). Females separate from their group to give birth to a calf at the beginning of the short rains in October and November (2) (3). Newborn calves are vulnerable prey for jackals, dogs, hyenas, and large cats and eagles (2).

Numbers of this rare antelope have recently drastically declined and the species is now in danger of imminent extinction (2). As the sole surviving species of the once abundant Beatragus genus (3), the hirola's extinction would mean not only the loss of a species, but also the loss of an entire ancient antelope group. Discovered in 1888 by the big game hunter and zoologist H.C.V. Hunter (4), the hirola is a sandy-coloured antelope with long legs, body and face and a short neck (2). Male hirolas turn slate-grey as they age (2). The face is characterised by white 'spectacles' around the eyes linked by a narrow, white chevron (2) (5), and pronounced, dark scent-glands under the eyes become enlarged when excited, leading to the hirola's other name of 'four-eyed antelope' (4). The lyrate, heavily-ringed horns are beautiful but dangerous weapons, used in fights with rivals. The thick skin at the nape of the hirola's neck folds up behind the horns when the ears are pricked, offering a degree of protection against the sharp horns of an opponent (2). The black-tipped ears and long tail are startlingly white (2).

The Hirola is endemic to north-east Kenya and south-west Somalia. Historical distribution is estimated to have covered ca. 17,900 km² in Kenya and ca. 20,500 km² in Somalia (Bunderson 1981, East 1999, Butynski in press). In Kenya, Hirola currently occur between Garsen, Bura and Galma Galla/Kolbio over an area of ca. 8,000 km² (Butynski 1999). Current status in south-west Somalia is not known, but its former range has been badly affected by prolonged civil and military conflicts that continued up to early 2007.

There is a small translocated population in Tsavo East National Park, outside the species’ natural range. This originated from a translocation of 30 animals from Garissa District conducted in 1963. It is thought that most of these perished soon after release and that the size of the “effective founder population” was only 11 to 19 animals (Butynski 1999). A further 10 animals were translocated to Tsavo East in 1996 (Hofmann 1996).

Hirola are found in the area between the Tana River in Kenya and the Juba River in Somalia. In 1963 a small population of about 20 individuals were introduced into the Tsavo East National Park from the South Garissa District.

Biogeographic Regions: ethiopian (Introduced , Native )

Historically the hirola may have had a large distribution, but since the 1960s it has been confined to a rapidly shrinking corner of south-east Kenya and southern Somalia (2). It is now thought to possibly be extinct in Somalia (5).

Hirola have long legs, a long body, long face with a slightly convex forehead, and a relatively short neck. Total body length ranges from 1200 to 2050 mm, tail length from 300 to 450 mm, and height at the shoulder from 1000 to 1250 mm.

Generally a mixture of soft and coarser hairs that vary in color from sandy brown to slate grey cover the body. The ears are white with black tips and the tail is white. A white line passes across the forehead from one eye to the other creating a white emphasis around the eyes in the likeness of a mask.

The horns of both males and females are angular, curved, and slightly flared. They are ringed most of the length of the horn, and reach about 700mm in length when fully developed.

Range mass: 65 to 155 kg.

Range length: 1200 to 2050 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger; ornamentation

Habitat and Ecology

Systems

• Terrestrial

Beatragus hunteri inhabits short-grass, seasonally arid, grasslands in dry acacia bush/scrub and forest-savannah mosaic habitats.

Suitable grazing lands change over time as they become unsuitable by the invasion of predators or large herds, drought, or over-growth of grasses. The largest known area grazed by a herd is over 100 square km.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: savanna or grassland ; scrub forest

The remaining hirolas inhabit a narrow strip of seasonally arid, grassy plains (2).

Hirola are selective grazers, depending on short grasses. Occasionaly they have been oberserved to consume forbs. Their selectivity creates a need to follow the progress of newly sprouting grasses on the savannah and grasslands. If grasses grow too long, or if the grasses are disturbed by other grazers, they will move to another area.  Early evening and morning are the times of highest intensity feeding.

Hirola are able to survive lengthy periods without drinking by avoiding energetic activities and storing fats.

Grasses eaten include Panicum infestum, Digitaria rivae, and Latipes senegalensis. Forbes eaten include Portulaca oleraceae, Commelina erecta, and Tephrosia subtriglora.

Plant Foods: leaves; wood, bark, or stems

Primary Diet: herbivore (Folivore )

It is likely that hirola play an important role in their habitats by influencing the growth and composition of plant communities. They also act as important prey species for large predators.

In the Garissa area, hirola are preyed on by lions and hunting dogs, while in the Tsavo region, they are preyed on by cheetahs and lions. Hyenas and eagles prey on young soon after birth and before the mother and calf rejoin the herd. Poaching plays a role in the 'predation' of Hirola. The poachers are composed of military personal, civilians, herdsmen, and local gangs.

Hirola avoid predation by remaining in the herd, thereby relying on the vigilance of many individuals.

Known Predators:

• lions (Panthera leo)
• African wild dogs (Lycaon pictus)
• cheetahs (Acinonyx jubatus)
• hyenas (Hyaeninae)
• eagles (Accipitridae)
• humans (Homo sapiens)

Damaliscus hunteri is prey of:
Accipitridae
Homo sapiens
Panthera leo
Acinonyx jubatus
Lycaon pictus
Hyaeninae

This list may not be complete but is based on published studies.

Preorbital gland secretions and posturing are used in male-male competition for access to females. Females are also likely to communicate their reproductive state via chemical cues.

Communication Channels: visual ; chemical

Perception Channels: visual ; acoustic

In captivity, the average lifespan of hirola is 10.2 years. Lifespan in the wild is unknown (Huffman, 2001; Solomon Kyalo, pers.comm.).

Average lifespan

Status: captivity: 10.2 years.

Observations: Little is known about the longevity of these endangered animals, but one captive specimen lived 15.2 years (Richard Weigl 2005).

Males compete among themselves for access to females and generally defend territories in which they maintain a harem of about 7 or 8 females. Male posturing includes head-flagging, marking of grass stems with preorbital glands, ground scraping with their hooves, and dung accumulations. Aggressive fighting between males is different from play-fighting by their stance. Earnest fights take place on their knees, whereas play-fighting takes place in an upright position.

Mating System: polygynous

Hirolas mate at the beginning of the long rainy season in March or April and gives birth at the beginning of the short rainy season in October and November. Gestation typically lasts 7 to 8 months and a single calf is born, though twins are possible. Females become sexually mature at 2 to 3 years of age, while males do not mate until they are large enough and dominant enough to successfully compete with other males, usually between 3 to 4 year old.

Breeding interval: Hirolas breed once yearly.

Breeding season: Breeding occurs in March and April.

Range number of offspring: 1 (low) .

Average number of offspring: 1.

Range gestation period: 7 to 8 months.

Range age at sexual or reproductive maturity (female): 2 to 3 years.

Range age at sexual or reproductive maturity (male): 3 to 4 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Females nurse and care for their young, who are capable of standing and running soon after birth. Calving females will separate from the group for the two weeks following birth. During this time the female and the calf are vulnerable to predation. When the calf has reached yearling status, it separates from the herd to join a sub group of yearlings.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female); post-independence association with parents

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Hirola populations suffered two drastic declines during 1976-1978 and then in 1995. In 1976-1978 the population declined from 14,000 individuals to about 2,000 for unknown reasons. The second decline saw the population decrease from ~2,000 to 300, this decline was attributed to hunting by poachers, competition with cattle, and loss of habitat due to human encroachment. The natural habitat of hirola occurs in southwestern Somalia and southeastern Kenya, though the Somalian population is thought to be extinct or only occuring in small patchy groups. Hirola are considered one of the world's rarest species.

Conservation efforts have been underway for this species since 1963 when they were reported to be threatened. A small population was relocated in Tsavo East National Park and placed under protection by the park. By 1996 the population had reached 56 individuals. That same year, 35 more individuals were relocated to the park from Kenya in the operation "Hirola Now or Never" to increase the genetic diversity of the park population.

Efforts are being made to study the wild populations and to immplement community programs to educate local people about this species and how to help conserve it.

(Solomon Kyalo, pers. comm.)

US Migratory Bird Act: no special status

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: critically endangered

Classified as Critically Endangered (CR) on the IUCN Red List 2007 (1).

Population

Population Trend

Major Threats

Numbers of hirola have declined severely; from 10,000 in the 1970s, to just 300 in 1995 (2). The remaining tiny population is now considered to be at risk of imminent extinction (2). Competition with cattle, severe drought, disease and poaching are all factors that have contributed to devastating hirola populations (3) (4). Unfortunately, the hirola's preference for areas that are used by livestock puts them at increased risk from diseases like rinderpest and tuberculosis (3).

Conservation Actions

In 1963, 10 to 20 hirola were released into Tsavo East National Park, Kenya, which grew to a population of 79 individuals by 1996. In 1996, another 29 hirola were translocated into the Tsavo East population, resulting in an estimated population of 100 hirola in Tsavo East National Park (6). The Hirola Management Committee (HNC) was also formed in 1994, with the aim of conserving this species in their natural range. The HNC created the Hirola Strategic Management Plan which outlined hirola conservation measures for the next five years (7). This included creating protected areas, reducing exposure to livestock diseases, careful monitoring, and promoting income generating eco-tourism for this unique species (7); measures that will hopefully pull this beautiful antelope back from the edge of extinction.

There are no known negative effects of hirola on humans.

Hirola are sometimes hunted for meat, they have suffered drastic declines as a result of overhunting in the past.

Positive Impacts: food