Climate change may be causing some monkeying around. In Kenya, a type of guenon known as De Brazza’s monkey has been found in novel terrain, with a large population discovered east of the Great Rift Valley in the Samburu district.
The valley is a huge fissure in the Earth’s crust, several million years old and stretching thousands of miles through east Africa, across the Red Sea, to Syria. This geologic formation is the result of active plate tectonics, where crustal plates are moving apart. In the past, the valley has served as a physical barrier for many species, while hosting its own unique ecosystem.
De Brazza’s monkeys are found in equatorial Africa from Cameroon in the west to Kenya and Ethiopia in the east. Large primates, they can reach up to five feet in length and live in various habitats, from swamp to dry mountain forest, spending much of their time in trees. Groups may have up to 35 members. These monkeys are slow, quiet, and unusually reticent; they tend to avoid contact with other species. A typical response to threat is to stay still – for up to eight hours. Such secretive habits make them difficult to track or count. Studies have found that these monkeys have high juvenile mortality (20-23% die in the first year) and breed relatively slowly; as a result, populations do not grow quickly. Until now, only about 700 De Brazza’s monkeys were known in Kenya. The Samburu population is estimated at 200-300 individuals.
These new groups live at higher altitude than other populations. Lower on the mountains, people have established settlements; human encroachment is one of the major threats to De Brazza’s monkeys. Forest habitats are deforested to make way for farmland; plant species important to the monkeys’ diet are used as livestock feed. Natural timidity makes them less likely to adapt to humans living nearby.
Despite the positive aspect of greater De Brazza’s monkey numbers, conservationist Louis Leakey is concerned that this new population may be one example of a long-term shift in the climate. The African continent already struggles with issues of drought and high temperatures, and the scenario with global warming only intensifies these problems. While this species can extend into drier forests, other species may not have that option.
