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:
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
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.
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
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 )
Taxonomy of hirola has been a point of debate for many years. Hirola were considered a subspecies of topi in 1977, giving it the name Damaliscus lunatus hunteri, later they were given specific status as Damaliscus hunteri. Recently they were placed in their own genus, Beatragus, as B. hunteri. Hirola are in the subfamily Alcelaphinae based on DNA evidence and morphology.
(Solomon Kyalo, personal communication)
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 ; tactile ; acoustic ; chemical
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
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
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.
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 )
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); sexual ; 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
In 2012, Beatragus hunteri was included among the world's 100 most threatened species in a report by the IUCN Species Survival Commission and the Zoological Society of London.
The hirola (Beatragus hunteri), also called the Hunter's hartebeest or Hunter's antelope, is a critically endangered antelope species found on the border between Kenya and Somalia. It was first described by the big game hunter and zoologist H.C.V. Hunter in 1888.[3][4] It is the only living member of the genus Beatragus, though other species are known from the fossil record.[2] The global hirola population is estimated at 300–500 animals and there are none in captivity.[5][6][7] 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".[8]
The hirola is a medium-sized antelope, tan to rufous-tawny in colour with slightly lighter under parts, predominantly white inner ears and a white tail which extends down to the hocks. It has very sharp, lyrate horns which lack a basal pedicle and are ridged along three quarters of their length. As hirola age their coat darkens towards a slate grey and the number of ridges along their horns increases. Hirola have large, dark sub-orbital glands used for marking their territories and give them the name "four-eyed antelope". They have white spectacles around their eyes and an inverted white chevron running between the eyes. The horns, hooves, udders, nostrils, lips and ear tips are black. Males and females look similar although males are slightly larger with thicker horns and darker coats.[9][10][11][12][13][14]
Several sources have recorded precise measurements from both captive and wild hirola. The following are maximum and minimum values taken from all sources: height at the shoulder: 99–125 cm, body weight: 73–118 kg, head and body length: 120–200 cm, horn length: 44–72 cm, horn spread (greatest outside width): 15–32 cm, tail length: 30–45 cm, ear length: 19 cm. It is not stated whether horn length was measured direct from base to tip or along the curve of the horn.[11][12][14][15] There is no data on how long hirola live in the wild but in captivity they have been known to live for 15 years.[5]
Authorities agree that the hirola belongs in the subfamily Alcelaphinae within the family Bovidae but there has been debate about the genus in which it should be placed. The Alcelaphinae contains hartebeest, wildebeest and topi, korrigum, bontebok, blesbok, tiang and tsessebe.[14]
When it was first described the hirola was given the common name Hunter's hartebeest. Despite this it was placed in the genus Damaliscus with the topi and given the scientific name Damaliscus hunteri.[9] Newer theories have classified it as a subspecies of the topi (Damaliscus lunatus hunteri)[16][17] or placed it within its own genus as Beatragus hunteri.[18][19][20][21]
Recent genetic analyses on karyotypic and mitochondrial DNA support the theory that the hirola is distinct from the topi and should be placed in its own genus.[20][22] They also indicate that the hirola is in fact more closely related to Alcelaphus than to Damaliscus. Placing the hirola in its own genus is further supported by behavioural observations. Neither Alcelaphus nor Damaliscus engage in flehmen, where the male tastes the urine of the female to determine oestrus. They are the only genera of bovids to have lost this behaviour. Hirola still engage in flehmen although it is less obvious than in other species.[23][24]
The genus Beatragus originated around 3.1 million years ago and was once widespread with fossils found in Ethiopia, Djibouti, Tanzania and South Africa.[12][19][25][26]
The hirola is adapted to arid environments with annual rainfall averaging 300 to 600 millimetres (12 to 24 in). Their habitats range from open grassland with light bush to wooded savannahs with low shrubs and scattered trees, most often on sandy soils.[27] Despite the arid environments they inhabit, hirola appear to be able to survive independently of surface water.[27][28] Andanje observed hirola drinking on only 10 occasions in 674 observations (1.5%) and all 10 observations of drinking occurred at the height of the dry season. Hirola do however favour short green grass and in 392 of 674 observations (58%) hirola were grazing on growths of short green grass around waterholes.[29] This association with waterholes may have led to reports that hirola are dependent on surface water.[14]
Hirola are primarily grazers but browse may be important in the dry season.[30] They favour grasses with a high leaf to stem ratio and Chloris and Digitaria species are believed to be important in their diet.[12][24] Kingdon does not consider the ecological requirements of the hirola unusual and in fact considers them to be more generalist than either Connochaetes spp. or Damaliscus.[12] A vet who examined the digestive tract of several hirola concluded that they were well adapted to eating dry region grasses and roughage.[31] They feed on the dominant grasses of the region and Kingdon (1982) believes that quantity is more important than quality in the hirola's diet.[24]
Hirola are often found in association with other species, particularly oryx, Grant's gazelle, Burchell's zebra and topi. They avoid Coke's hartebeest, buffalo and elephant.[32] Whilst hirola avoid direct association with livestock, they reportedly prefer the short grass in areas where livestock have grazed.[30]
Female hirola give birth alone and may remain separate from the herd for up to two months, making them vulnerable to predation. Eventually the female will rejoin a nursery herd consisting of females and their young. Nursery herds number from 5 to 40 although the mean herd size is 7-9. They are usually accompanied by an adult male.[12][24][30][33]
Young hirola leave the nursery herd at around nine months of age and form various temporary associations. They may gather together in mixed or single sex herds of up to three individuals; sub-adult or subordinate adult males may form bachelor herds of 2-38 individuals; female sub-adults may join an adult male and; if no other hirola are present, young hirola may attach themselves to a herd of Grant's gazelles or simply spend most of their time alone.[29][30]
Adult males attempt to secure a territory on good pasture. These territories are up to 7 square kilometres (2.7 sq mi) and are marked with dung, secretions from the sub-orbital glands and by stamping grounds where males scrape the soil with their hooves and slash the vegetation with their horns.[30] It has been suggested that at low population densities adult males abandon territory defence and will instead follow a nursery herd.[34] Nursery herds do not defend a territory but do have home ranges which overlap the territories of several adult males.[32] The size of a nursery herd's home range varies from 26 to 164.7 square kilometres (10.0 to 63.6 sq mi) with a mean size of 81.5 square kilometres (31.5 sq mi).[29]
Nursery herds are relatively stable but bachelor herds are very unstable with a fission fusion dynamic. In the 1970s hirola were observed forming aggregations of up to 300 individuals to take advantage of scarce, but spatially clumped, resources during the dry season (Bunderson, 1985). Information is lacking on male territoriality and how it relates to mating success, how and when hirola join a herd and how new herds are established (Butynski, 2000).
Hirola are seasonal breeders with young being born from September to November.[12] Data on age of sexual maturity and gestation period are not available for wild hirola however in captivity gestation was around 7.5 months (227–242 days) with one female mating at 1.4 years old and giving birth at 1.9 years. Another pair of hirola mated when they were 1.7 years of age.[35] In captivity one of the main causes of mortality is wounds caused by intra-hirola aggression, including aggression between females.[5]
The reasons for the historic decline of the hirola are not known but is likely a combination of factors including disease (particularly rinderpest), hunting, severe drought, predation, competition for food and water from domestic livestock and habitat loss caused by bush encroachment as a result of the extirpation of elephants within its range.[14][36]
This hartebeest prefers areas that are used by livestock which puts them at increased risk from diseases like tuberculosis.[37] It might be vulnerable to poaching, and is also subject to the natural phenomena of predation and competition with other wild herbivores, particularly topi and Coke's hartebeest, which the IUCN also calls 'threats'.[38]
The hirola's natural range is an area of no more than 1,500 km2 on the Kenyan-Somali border, but there is also a translocated population in Tsavo East National Park. The natural population in the 1970s was likely to number 10,000–15,000 individuals but there was an 85–90% decline between 1983 and 1985. A survey in 1995 and 1996 estimated the population to number between 500 and 2,000 individuals with 1,300 as the most reasonable estimate. A 2010 survey estimated a population of 402–466 hirola.[6]
A translocated population was established in Kenya's Tsavo East National Park with translocations in 1963 and 1996 (Hofmann, 1996; Andanje & Ottichilo, 1999; Butynski, 1999; East, 1999). The 1963 translocation released 30 animals and the first survey in December 1995 concluded that there were at least 76 hirola present in Tsavo at the time. Eight months later a further 29 translocated hirola were released in to Tsavo, at least six of which were pregnant at the time (Andanje, 1997). By December 2000 the hirola population in Tsavo had returned to 77 individuals (Andanje, 2002) and by 2011 the population was estimated at 76 individuals.[5][7]
In 2013, 9 individuals from 7 different herds were fitted with GPS-collars, scheduled to drop-off in June 2014, in north-eastern Kenya. This marked the first time that the species was GPS-collared in the wild. These collaring events served as a purpose to understand the basic ecology, the natural history, movements patterns and population demographics of the species.[39]
Hirola are critically endangered and their numbers continue to decline in the wild. There are between 300–500 individuals in the wild and none currently in captivity.[5][6][7]
Despite being one of the rarest antelopes, conservation measures for the antelope have so far been marginal. The Arawale National Reserve was created in 1973 as a small sanctuary for them, but has been left unmaintained since the 1980s. In 2005, four local communities in the Ijara District, in collaboration with Terra Nuova, established the Ishaqbini Hirola Conservancy.[40][41] As of 2014, a 23 km2 predator-proof fenced sanctuary has been constructed at Ishaqbini and a founding population of 48 hirola is breeding well within the sanctuary.[42]
The hirola (Beatragus hunteri), also called the Hunter's hartebeest or Hunter's antelope, is a critically endangered antelope species found on the border between Kenya and Somalia. It was first described by the big game hunter and zoologist H.C.V. Hunter in 1888. 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".
