Chimpanzees in Senegal: Neighbors of the Savannah
Painfully creaking from side to side, our car made its way slowly down the rough narrow road from Bassari country. Boiro and I were busily chatting away with the windows rolled up and the air conditioner on, when I thought I heard muffled cries from outside. Braking suddenly, I jolted the car to a halt and motioned to Boiro to roll down the window. A hot gust of dry air burst through the opening, carrying with it a familiar sound. Big smiles stretched across our faces as we both recognized the hoots and calls of chimpanzees. Although their vocalizations were no different from our rehabilitated chimpanzees in Gambia, there was something very special about the fact that these were wild chimpanzees.
Samba Boiro had worked with me for nearly 20 years. Though based in neighboring Gambia with the rehabilitation project, he often traveled with me in Senegal and Guinea, providing assistance and learning more about chimpanzees. Fluent in most of the local languages as well as knowledgeable of chimpanzees, Boiro’s brief presence on this trip greatly facilitated my work for FoA conserving chimpanzees in Senegal. Souleye N’diaye, the previous director of Senegal’s National Park Office, was now working with me on this activity and was responsible for the survey component. He was currently in the field confirming chimpanzee presence along the boundary of Niokolo Koba. We were on our way to meet up with Souleye this afternoon in Kedougou when we had the pleasure of seeing the chimpanzees.
Surprisingly, the group of eight chimpanzees did not run away, but instead sat perched on the fat branches of the fruit-laden baobab trees, giving alarm calls at our big, noisy white vehicle. Our car remained in position, rudely obstructing the green landscape of the narrow ravine. Quietly opening the door and slowly slipping out of the car, we both took crouching, less threatening positions along the edge of the road. We spent nearly 15 minutes watching the chimpanzees before they slithered down the trees and quietly moved over the hill and out of our sight. For the next two hours, we talked incessantly of our luck in seeing the chimpanzees, remarking on how the large male had thighs bigger than Dash and laughing at how one chimpanzee had a southern drawl exactly like our chimpanzee Lily. Seeing chimpanzees on our last afternoon was a perfect closing to our two-week stay in southern Senegal.
Chimpanzees are few and far between in Senegal. They inhabit the northernmost point of the range of the highly endangered western chimpanzee and are often referred to as “savannah” chimpanzees. No one is sure how many still survive in this marginal habitat, but the total population is estimated between 300 – 600 individuals. The first task in trying to save these chimpanzees is to collect current and accurate information including a reliable estimate of the total population, details of their distribution and factors that restrict and threaten their survival. For this reason, FoA has embarked on a survey of roughly 24,000 square kilometers, 10,000 of which is allocated to the Niokola Koba National Park. Based on the above figures one can imagine how difficult it must be to find an elusive nomadic chimpanzee at the rate of one individual per 40 to 80 square kilometers.
Fortunately, for both our budget and work schedule, we don’t need to send out a search team to find and count each chimpanzee. Scientists have devised a systematic method for estimating chimpanzee populations by counting their nests. The total land area presumed to support chimpanzees is divided into equal sections. A representative sample of the sections is randomly selected, and straight lines or transects are walked and nests counted. These numbers are plugged into an equation, which provides an estimate of the number of chimpanzees living in the sampled area. Although this methodology has proven effective in more forested areas, we are finding it both time-consuming and tedious in Senegal, as nearly all transects result in no nests being counted. One of the reasons for this is that the region in which the chimpanzees live is a very harsh, dry environment with few places left for large bodied chimpanzees to hide. They need shade as well as water to drink on a daily basis, which in this habitat translates as gallery forest. Less than 5% of the total area we set out to survey is gallery forest. In an attempt to learn more about the chimpanzees, we are now focusing on gallery forest habitat and recruiting the assistance of local residents in counting nests and chimpanzees.
Although knowing the number of chimpanzees is a necessary first step, this knowledge, on its own, will not conserve chimpanzees in Senegal. One of the unique characteristics of savannah chimpanzees is their proclivity of living side by side with their homo sapien cousins. Chimpanzees in Senegal cohabit with a number of ethnic groups including the Bassari, Coniagui, Tenda, Diahonke and Fulani. Although chimpanzees are not hunted or eaten by these groups, their survival is threatened by human imposed activities, most importantly habitat destruction and fragmentation. Chimpanzees and humans harvest some of the same natural resources, including many wild fruits, honey and water. Competition over water has been recorded in several areas and is also considered a threat to the survival of chimpanzees in this area. Determining the nature of the competition and providing sustainable resolutions that assist both species to survive is a major objective of our work.
Stay tuned for part two in FoA’s research and development of approaches to help save the reducing number of chimpanzees in Senegal.