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Kenya’s Elusive Patas Monkeys

Yvonne de Jong is a National Geographic grantee working to track down what may be Africa’s least understood large animal, the Desert Warthog.

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An extremely hot and dusty road leads us northwards along the Kenya-Uganda border. We are in West Pokot District, central western Kenya. Despite what appears suitable habitat, no warthog (Phacochoerus sp.) will expose itself to us in this heat, and neither will the Guenter’s dik-dik (Madoqua guentheri), olive baboon (Papio anubis) or any other mammal that we hope to encounter in the region. The bags of ‘home-made’ charcoal on offer along the side of the road tell us that there are more human settlements and farms tucked away in the bush here then we had expected.

Adult male Namaqua dove (Oena capensis) at Konyao, central western Kenya. Photograph by Yvonne de Jong & Tom Butynski.

Adult male Namaqua dove (Oena capensis) at Konyao, central western Kenya. Photograph by Yvonne de Jong & Tom Butynski.

The area is not entirely new to one of us (YDJ). Ten years ago, YDJ surveyed this area in search of the nationally threatened eastern patas monkey (Erythrocebus patas pyrrhonotus), one of Kenya’s most attractive but also elusive primates (see ‘Monkey in Red‘ at www.wildsolutions.nl). Although no patas were seen,  strong evidence of their presence was obtained by interviewing residents—a common method used when studying large, distinctive mammals that are at low densities and have vast home ranges (20 – 80 km²).

Butynski & De Jong - 2013 - West Pokot

East of Konyao, central western Kenya. Warthogs were reported to be present but heavily hunted in this area. No warthogs were seen here, no doubt because they are shy and at low densities. Olive baboons (Papio anubis), eastern patas monkeys (Erythrocbus patas pyrrhonotus) and Hilgert’s vervet monkeys (Chlorocbus pygerythrus hilgerti) are patchily distributed in this area. Photograph by Tom Butynski & Yvonne de Jong.

While working our way northwards we often stop to scan the area for wildlife, to talk to the older residents, or to photograph the vegetation and scenic landscape.  The message that we repeatedly get from the local people is painfully clear—YES, warthogs are here, BUT densities are low and they are very shy as a result of heavy hunting. This is not entirely surprising or new to us —we know that warthogs are considered to be particularly tasty. The good news is that many people say that the patas monkey still survives here, albeit in low numbers. All of the residents who make mention of patas refer to its presence in the same areas where it was said to occur during YDJ’s survey of 10 years ago.

Adult male eastern patas monkey (Erytrocebus patas pyrrhonotus). Drawing by Stephen Nash, Conservation International.

Adult male eastern patas monkey (Erythrocebus patas pyrrhonotus). Drawing by Stephen Nash, Conservation International.

Patas monkeys are shy, cryptic, silent and fast—traits which make them particularly hard to find, let alone study in the wild. Patas are omnivores, eating gum, anthropods, leaves, flowers, fruits  and, occasionally, small mammals, reptiles, birds and eggs. They need to drink daily. Patas are  semi-terrestrial, preferring savannah-woodlands, particularly those dominated by acacia.

Patas can out-run most of their predators with ease as they are able to reach a speed of about 55 km/h when in open habitats. As the fastest of the world’s primates, they often flee on the ground (whereas most primates seek refuge in trees). Their reliance on open habitats to out-run predators makes them wary of dense vegetation.

Eastern patas monkey (Erythrocebus patas pyrrhonotus) on Ole Naishu Ranch, Laikipia Plateau, central Kenya, in savannah-woodland dominated by whistling thorn (Acacia drepanolobium) and magic gwarra (Euclea divinorum). Photograph by Yvonne de Jong and Tom Butynski.

Eastern patas monkey (Erythrocebus patas pyrrhonotus) on Ole Naishu Ranch, Laikipia Plateau, central Kenya, in savannah-woodland dominated by whistling thorn (Acacia drepanolobium) and magic gwarra (Euclea divinorum). Photograph by Yvonne de Jong and Tom Butynski.

Historically, patas occupied large parts of southern, central, western and north-western Kenya, an estimated range of 88,800 km² (see ´Distribution and Conservation of the Patas Monkey Erythrocebus patas in Kenya´ at www.wildsolutions.nl). Over the past 100 years, the large stretches of savannah-woodland and permanent water sources that patas rely on have been severely degraded or lost. What remains usually needs to be shared with an increasing number of people (Kenya’s human populatin doubles about every 20 years).

Patas habitat, although marginal for growing crops, is being exploited by farmers who have no alternative. In short, the human population over the range of patas is expanding extremely rapidly, using the natural resources unsustainably, and threatening the species’ survival in Kenya. Our survey in 2008 indicates that the population of patas in Kenya declined approximately 46% since 1995, that the geographic range has been reduced to roughly 48,000 km², and that much of this range is both fragmented and degraded.

De Jong & Butynski - patas - Kenya

Captive adult female eastern patas monkey (Erythrocebus patas pyrrhonotus) from the Laikipia Plateau, central Kenya. Photograph by Yvonne de Jong & Tom Butynski.

Habitat loss, habitat degradation and competition over water and habitat are not the only factors putting the patas monkey at risk in Kenya and elsewhere. Interviews with almost 210 residents in western Kenya (including Busia, West-Pokot and Southern Turkana Districts) in 2004 indicated that patas are crop raiders in some places. As such, farmers chase and sometimes kill patas (see ‘Guess Who’s Coming to Dinner’).

Hilgert's vervet monkey (Chlorocebus pygerythrus hilgerti) hiding in the canopy of a fig tree at the edge of a 'shamba' (Kiswahili for garden) in riverine vegetation in central western Kenya. Primates are shy and wary in this area as they are chased, and sometimes killed, by farmers protecting their crops. Photograph by Yvonne de Jong & Tom Butynski.

Hilgert’s vervet monkey (Chlorocebus pygerythrus hilgerti) hiding in the canopy of a fig tree at the edge of a ‘shamba’ (Kiswahili for garden) in riverine vegetation in central western Kenya. Primates are shy and wary in this area as they are chased, and sometimes killed, by farmers protecting their crops. Photograph by Yvonne de Jong & Tom Butynski.

During the present survey we soon realize that not only the warthogs and patas monkeys are highly cautious and difficult to observe. When we encounter a group of vervet monkeys feeding in a tall fig tree just outside a small village we are immediately surrounded by kids exhibiting their stone throwing skills. As a result, the group of vervets flees into the denser canopy. Similarly, olive baboons are harassed by people attempting to keep them way.  We do not see baboons in this area but we do hear them calling from their night sleeping sites. Despite many hours of searching we fail to see warthog (yet residents state that they are present). Guenter’s dik-dik and two species of ground squirrel, the striped ground squirrel (Euxerus erythropus) and the unstriped ground squirrel (Xerus rutilus), are seen on the road.

The common genet (Genetta genetta) that we spot during a nocturnal survey in vegetation along the Suam River, gives us good looks before climbings up into dense vegetation. Despite our many long nocturnal drives and walks, we only encounter two galagos, presumably the northern lesser galago (Galago senegalensis)—but they are gone before we can identify them with certainty. Just when we thought all wildlife in the area had an agreement to dash off when we arrive, a surprisingly calm African civet (Civettictis civetta) appears. This beautiful short- legged mammal emerges right at sunset from a dense clump of vegetation (presumably its day-time sleeping site) and strolls around our little camp. Some mesmerizing minutes later it walks off into the darkness as we make ourselves ready for a night survey.

Common genet (Genetta genetta) in  vegetation along the Suam River at Nakujit, West Pokot District, central western Kenya. Photograph by Yvonne de Jong & Tom Butynski.

Common genet (Genetta genetta) in vegetation along the Suam River at Nakujit, West Pokot District, central western Kenya. Photograph by Yvonne de Jong & Tom Butynski.

Days later we leave the area to continue our quest for warthogs—driving farther north into southern Turkana. Not much luck with West Pokot’s warthogs this time round but it is satisfying to learn that they, patas monkeys, and several other mammals continue to occur there.

Epauletted fruit bat (Epomophorus sp.) feeding on a fig at Marich Pass, central western Kenya. Photograph by Yvonne de Jong & Tom Butynski.

Epauletted fruit bat (Epomophorus sp.) feeding on a fig at Marich Pass, central western Kenya. Photograph by Yvonne de Jong & Tom Butynski.

To learn more about patas monkeys, visit www.wildsolutions.nl for photographs, maps and  publications.

 

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