Yvonne de Jong is a National Geographic grantee working with team member Thomas Butynski to track down what may be Africa’s least understood large animal, the Desert Warthog.
The Huri Hills, a remote region of large lava cones, is located between the Chalbi Desert and the Kenyan-Ethiopian border in central-north Kenya. These hills rise about 300 meters (985 feet) above the lava plateau, reaching 1524 meters (5000 feet) above sea level. Just north of the Huri Hills, separated by a descending plain of black-cotton-soil, lies the granitic Mount Forole (1887 meters; 6200 feet). This sacred mountain marks the Kenyan-Ethiopian border.
During November 2013 we surveyed the Huri Hills, the lava plains to the northwest, and Mount Forole’s southern foothills. From the barren lava plains of the northern Chalbi Desert, east of Kalacha Oasis, the Huri Hills looked like an immense green mirage. Northern Kenya annually receives about 500 millimeters (20 inches) of rain. October and November are typically the peak of Kenya’s ‘short rains’.
Our survey seems spot on…recent good rains have left the Huri Hills and Mount Forole looking lush and inviting. It took some imagination to picture the Hills as dry as they are for most of the year.
The main focus of our visit to this region was to add to our understanding of the geographic range and conservation status of the desert warthog (Phacochoerus aethiopicus) in northern Kenya (See our earlier blog: Quest for Kenya’s Desert Warthog). In practice, however, we collect distribution and abundance information for many other species as northern Kenya is, biologically, a poorly-known region.
Where are the Warthogs?
In recent years we have compiled warthog records for eastern Africa from literature, colleagues, the web, and from our own field surveys. This is no record of warthogs in our database in the Huri Hills or the Mount Forole region…the nearest records are for Moyale [desert warthog, 120 km (75 miles) east of Mount Forole] and for south of Sibiloi National Park [common warthog, 175 km (110 miles) west of Mount Forole].
With great curiosity we start our survey in the hope of filling this ‘warthog distribution knowledge gap’. If we do find warthogs, will they be the desert warthog or common warthog (Phacochoerus africanus)?…or, perhaps, both!
The few residents (mainly members of the Gabbra tribe) we meet during this survey tell us that warthogs do occur in the region, albeit shy and uncommon. Unfortunately we were not able to confirm the presence of warthog in the Huri Hills. The lack of sightings might be largely due to the fact that the only available road through the Hills is on lava rock, a substrate not particularly suitable for the construction of warthog burrows.
The red sandy soils of the foothills of Mount Forole support grassy glades surrounded by (often dense) Acacia-Commiphora woodland, a vegetation type near perfect for a warthog. Here we encountered a sounder of six adult desert warthogs. Close inspection of the site revealed that these warthogs were apparently feasting on the succulent underground bulbs of Chlorophytum…a small (20 cm high) member of the asparagus family (Asparagaceae).
Warthogs have longer legs than other suids (pigs, hogs, boars). This, together with their short neck, mean that they typically forage while on their knees. With their strong, wide, snout they dig with a spade-like movement to reach roots, tubers, grubs, and other subterranean foods. Unlike common warthogs, desert warthogs lack incisors and, therefore, pick food items with their lips and gums.
Warthog footprints in these foothills were common and widespread, indicating that a fairly large population is present. We suspect that we had but one sighting because these warthogs are shy, perhaps predominantly nocturnal, and because the vegetation is often dense. Nonetheless, our newly obtained distribution dot on the desert warthog map provides significant insight into the geographic range of this poorly known large mammal.
Abundance of Birds
November appears to be the ideal month for encountering birds in northern Kenya. The relatively lush vegetation provides food and cover to many of the more than 120 bird species that migrate to Kenya from the Northern Hemisphere at about this time (kenyabirds.org.uk). During this survey we found an impressive diversity of birds in the Huri Hills and on Mount Forole. We have never experienced nights that were nearly so full of bird calls and songs.
The more common birds included Donaldson-Smith’s sparrow-weaver (Plocepasser donaldsoni), white-headed buffalo-weaver (Dinemellia dinemelli), crested lark (Galerida cristata), Somali short-toed lark (Calandrella somalica), pale prinia (Prinia somalica), grey wren warbler (Calamonastes simplex), Somali fiscal (Lanius somalicus), Somali golden-breasted bunting (Emberiza poliopleura), pygmy batis (Batis perkeo), Hunter’s sunbird (Chalcomitra hunteri), Heuglin’s bustard (Neotis heuglinii), and kori bustard (Ardeotis kori). Migrants included pallid harrier (Circus macrourus), common kestrel (Falco tinnunculus), northern wheatear (Oenanthe oenanthe), Isabelline wheatear (Oenanthe isabellina), pied wheatear (Oenanthe pleschanka), common rock thrush (Monticola saxatilis), and willow warbler (Phylloscopus trochilus).
The diversity and abundance of the larger mammals in northern Kenya is lower than in the central or southern part of the country. All of the species present need to be able to survive under seasonally high temperatures and to go without drinking water for several months at a time.
The most common antelopes in this region are Bright’s gazelle (Nanger notata) and Günther’s dik-dik (Madoqua guentheri). Bright’s gazelle live in the savannas of central and northern Kenya and remain widespread, albeit at low density. This species is notably absent from areas of dense bush on the red soils of the foothills of Mount Forole. Günther’s dik-dik were only encountered in the acacia bushlands on the foothills of Mount Forole. The many latrines (or ‘faecal middens’) on the bare red sandy soils indicated a healthy population. This species might now be absent from the Huri Hills.
A herd of at least seven greater Kudu (Tragelaphus strepsiceros) was seen in Acacia – Commiphora bushland on a rocky slope in the central Huri Hills. Two solitary Beisa oryx (Oryx beisa beisa) were encountered during this survey; one in Acacia – Commiphora bushland on the lava plateau north-west of the Huri Hills and one on black cotton soil on the Ngaso Plain.
Gerenuk (Litocranius walleri) were occasionally observed during this survey. These long-necked antelopes, named ‘swara twiga’ (giraffe gazelle) in Kiswahili, are able to stand on their hind legs to reach browse up to 2 meters (7 feet) above the ground.
One of the most evasive, yet widespread, large mammals of Africa, the aardvark (Orycteropus afer), was captured on three of our camera traps. The aardvark is the only member of the family Tubulidentata. They forage at night, moving slowly with their nose close to the ground sniffing for ants and termites, which they dig up and eat. To avoid predators, hot temperatures, and to minimize loss of moisture, aardvarks reside in 3 meter (10 feet) deep burrows during the day. Interestingly, warthog abundance appears to be linked to the occurrence of aardvark as they often ‘inherit’ abandoned aardvark burrows.
Kenya’s Non-human Primates
None of Africa’s arid regions hold more than a few species of primate. No non-human primates were encountered in the Huri Hills. In the Mount Forole foothills, however, we encountered Kenya’s largest and one of its smallest non-human primates-the olive baboon (Papio anubis) and the Somali lesser galago (Galago gallarum), respectively.
Baboons were often detected by their loud ‘wahoo’ call. This call can be heard to >2 km (>1 mile) and is frequently given from the sleeping cliffs in the early morning or at night when leopards (Panthera pardus) or other predators are near. Baboons were relatively common on Mount Forole, its foothills, and north-west of Huri Hills. As for our earlier baboon encounters in northern Kenya (see our earlier blog: Secret to Olive Baboon Survival in a Barren Desert), the groups here are relatively small at 15–30 individuals.
In wetter regions, groups are typically comprised of 30–60 individuals. As elsewhere in Kenya’s arid north, these baboons (indeed, all mammals) have limited access to drinking water most of the time, and no access to drinking water for several months at a time.
Although we constantly looked and listened for the Somali lesser galago (see our blog: New Population of Bushbabies Discovered in Northern Kenya), only one individual was encountered during this survey. This animal was detected when it gave alarm calls from a small grove of Commiphora trees near one of our camps on Mount Forole.
We had conducted a 7 km (4 mile) nocturnal walking survey in this area the evening before without seeing or hearing a single galago. This species must be at very low density at this site. This encounter provided a range extension for this species of 80 km (50 miles) to the west, removing yet another question mark from the distribution map of this poorly-known primate.
Passing Kwial Hill, while motoring east from Mount Forole towards Turbi town, rain clouds rapidly built-up over an extensive area of ‘black-cotton’ soil known as the Ngaso Plain. Black cotton is infamous and is to be avoided when even slightly wet. These clay soils become water-logged as a result of poor drainage due to a layer of lava underneath. When wet they become sticky and slippery, and difficult, if not impossible, to drive on.
As much of the region is still wet from the rains of the past several weeks, we hastened across the 80 km (50 mile) wide Ngaso Plain to Turbi. Here we met the dirt ‘highway’ that took us slowly over the (also very wet) Dida Galgula Lava Desert to Mount Marsabit.
Gabbra tradition forbids hunting, tree-cutting, or over-utilization of the grazing range – as do the laws of Kenya. In the wake of the rapid growth of the human and livestock populations of this region, however, there has been considerable environmental damage.
Unsustainable use of the natural resources has led to the loss of most of the larger species of mammals, including lion (Panthera leo), elephant (Loxodonta africana), black rhinoceros (Diceros bicornis), Grevy’s zebra (Equus grevyi), and giraffe (Giraffa camelopardalis). With this tragic loss of megafauna, the region no longer has the opportunity to develop a significant tourism industry based on animal viewing.
Notwithstanding the damage and loss to the environment, Huri Hills and Mount Forole continue to offer stunning scenery and a biodiversity that remains poorly-known and worthy of much further study. Beyond this, we found the traditional people of this region to be culturally interesting, pleasant, and helpful.
For more information on warthogs and our other research, past and present, please visit www.wildsolutions.nl. This site holds many photos, distribution maps, and pdfs of publications and reports.