Less than a hundred of the mountain bongos are left in the wild, teetering on the edge of extinction
Despite their elusive nature, the mountain bongo play a crucial role in their ecosystem as seed dispersers and prey for predators. Their conservation is vital not only for their own survival but for the overall health of the forest ecosystem they call home. The work of BSP hopes to help unravel the mysteries of mountain bongo biology and ecology in order to successfully protect them and conserve their habitats, along with other important species that inhabit them.
About the mountain bongo
Classified as a subspecies only in 2008, the mountain bongo or eastern bongo (tragelaphus eurycerus isaaci) is the world’s largest and heaviest forest dwelling antelope and it is endemic to Kenya. It is one of two subspecies of bongo, the other being the lowland or western bongo (tragelaphus eurycerus eurycerus), which inhabits lowland equatorial forests throughout the Congo basin and West Africa. Exceedingly shy animals, bongos are forest browsers exclusively, being restricted to densely forested areas with an abundant year-round growth of accessible under-storey leaves and shoots.
Bongos are known for their striking appearance, with a vibrant reddish-brown coat and striking white-yellow stripes along the body. It is a richly coloured and statuesque antelope, having a hunched, rather than a flat-backed, appearance. Both males and females have long, slightly spiralled horns. A large adult male can weigh as much as 405 kg (almost 900 pounds), while standing 1.3 metres (four feet three inches) at the shoulder and measuring fully 2.5 metres (more than eight feet) from nose to tail. Disposed down the shoulders, flanks and hindquarters are 11 to 14 striking vertical white stripes, and there are other white patches about the face and legs. The animal’s large, flared ears provide for excellent hearing.
Dark muzzle face, with stripes between the eyes and white spots on the cheeks
Only species of spiral-horned antelope in which box sexes have horns
Chestnut brown fur with 11 to 14 vertical white stripes along their sides
Habitat and range
Although bongo were found present in Eburru and Mt Kenya during the BSP teams early surveillance. No evidence in the last 3-5 years has indicated in Eburru and Mt Kenya, Bongo are still surviving. The low numbers discovered by BSP in these forests prevented any potential growth for these two areas. But with long term planning and with sufficient foods in these areas, there is every hope they can return to these previous habitats.
Behaviour and social system
Little is known about the social organisation of bongos in the wild due to their rarity and secretive nature. The females stick together, generally in small groups, each frequenting a circumscribed home range encompassing perhaps one or two thickly forested mountain ridges. On reaching maturity, young males leave the maternal group, and look for another group to join, outside their native home range. Older males often lead a largely solitary existence. Bongos are not thought to be territorial and, unlike many other antelope species, do not possess any obvious scent glands for marking. They are thought to be mostly crepuscular, many of our camera trap images are taken during the night, particularly in early morning (between the hours of 01:00 and 05:00) which means they are perhaps more nocturnal than originally thought.
Diet
Through our tracking and monitoring work, we have been studying the diet of bongos in the wild. They are both grazers and browsers and demonstrate selective habits, feeding on mountainside vegetation before retreating to rest and ruminate during the day in the safety of the dense forest undergrowth. They mostly appear to browse on leguminous plants, shrubs, vines and leaves, graze grasses in forest clearings and may eat some wild fruits. Interestingly, bongos are known to travel large distances to visit natural clearings in the forest where they consume salt and other minerals from the mud, soil and even burnt wood. These minerals may have a role in protecting them from certain toxic compounds in the plants they eat.
Conservation status
Late 1800s – early 1900s: First sightings
The Eastern, or Mountain Bongo (Tragelaphus Eurycerus Isaaci) was first introduced to Europeans at the close of the last Century as an “Antelope like a Zebra, with horns, but colored like a bushbuck with white stripes on either side”. For some years the Wanderobo Forest dwellers had been telling hunters of a mystical antelope that dwelt in the high mountain forests they called “Sulgoot”. This animal was seldom seen as it never came out of the thick undergrowth, had excellent hearing and eyesight, and was always on the alert and very shy.
F.J.Jackson C.B. a renowned Ornithologist, Administrator in Kenya, and finally Governor of Uganda, described the Bongo, and supplied a set of horns to the Zoological society in 1897, but likely this was lowland bongo. Jackson hunted far and wide for this animal and offered a reward to the Wanderobo to collect a specimen for him, but was not successful.
Firstly, a letter from a Major in the Uganda Rifles stationed at Eldama Ravine in Kenya, dated 13th August 1901 fully described a Bongo antelope that had been brought in to him by the Wandorobo.
Finally, Isaacs, a British Administrator stationed at Eldama Ravine actually saw this antelope as it vanished, through the heavy undergrowth. The first (female) specimen was reported and detailed in a letter by Isaacs dated 4 Oct 1901 to The Times editor and several articles were published about this newly identified antelope. The mountain bongo was named after Isaacs.
1910s to 1970s: Hunting trophy and population decline
The first ever photos of Bongo in the wild were taken by a Gandar Dower who set up a camera in the Southern Aberdares with a trip wire across a game path. These were published in a book written in 1948.
On 6th November 1932, Major Eric Sherbrooke Walker opened the Tree Tops hotel within the Forest Reserve of the Aberdares. Fun facts: This hotel became famous for being the location where the Princess Elizabeth became the Queen of England after the death of her Father, King George IV. On that first night, it is recorded a group of 8 Bongo came into the waterhole at 11 pm.
After the Roosevelt Safari in 1910, the Bongo became the prime trophy for sportsmen who came to Kenya from all over the world. The bongo was restricted to 1 kill per license at a fee of 75/ Kenyan Shillings. By the game Dept. Records for 1960, only two Bongo were actually taken from 20 licenses issued. In the 70’s licenses were issued to capture Bongo to export to foreign Zoos and Game Parks.
Alan Root was the first who successfully captured Bongo in the Aberdares and Eburu. There are no records of how many were successfully caught, but from conversations to old trackers involved, many of the bongo taken probably died in capture and transport from the forests.
In the 1980s, the bongo’s range extended across the forests Kenya and it could be found in: the Aberdare Ecosystem, Mt. Kenya National Park, Mau South West Forest Reserve and Mau Eburru Forest Reserve, Mt. Londiani, Chemorogok and Lembus adjacent forests and Cherangani hills
The next Bongo photograph was taken by the world renowned photographer Peter Beard in late 1960s or early 70s. Within the Aberdare Park, he set up a camera. Once fresh Bongo signs were seen he would sit and wait for a bongo to come in sight.
Current distribution and challenges
In the last few decades there has been a rapid decline in numbers due to hunting, poaching and human pressure on habitat. In Kenya, the population of bongo has been on a downward trend and indeed in some of the ranges local extinction has been reported, these include the Cherangani and Chepalungu hills.
The continued existence of the mountain bongo is dependent on improved protection of the remaining isolated populations, as well as the conservation and monitoring of their forest habitat. Presently, there are more mountain bongos in captivity than in the wild. Efforts are being made to bolster wild populations by reintroducing captive-bred animals, with 18 impressive individuals arrived in Kenya in February 2004.
Through DNA sampling and analysis, BSP has also been able to determine the extent to which in-breeding within today’s wild population has compromised the subspecies’ genetic diversity. Of 113 samples of DNA tested to date, only two haplotypes have been identified (compared with 23 for waterbuck samples collected in the same areas). This suggests that the whole of today’s remaining mountain bongo population may be descended from just two maternal lineages.
BSP and its partners, such as KWS, are working with scientists and zoos around the globe to guarantee the successful progress of re-wilding initiatives and preserve genetic diversity.
Thanks to our unwavering dedication and support from our partners and donors, we have documented evidence of 70 individual calves in the Mau and Aberdares regions using camera traps since the start of our project.
We are grateful to our international and local partners, as well as individual contributors, for the photos used on this website. Thank you for your support.
