Max Planck Institute - Loango Ape Project

Project Background

In February 2005, the Max Planck Institute of Evolutionary Anthropology in collaboration with Operation Loango, initiated a project of wild lowland gorillas and chimpanzees within Loango National Park for the joint purposes of ecotourism and research. Under the direction of Professor Christophe Boesch and Dr Martha Robbins, a team of researchers and ecoguides began the slow process of habituating these great apes with two objectives.

Objectives

  1. The first objective is to begin a scientific study of the sympatric populations of gorillas and chimpanzees that live side by side within the park. During the habituation process, emphasis has been placed on differences in feeding ecology and habitat use between the two ape species. We are also interested in differences in social behavior and grouping patterns between the two species and among other populations of apes in Africa.
  2. The second objective is to habituate two groups of gorillas and one community of chimpanzees for ecotourism purposes, allowing visitors the opportunity to see these animals in their natural environment.

Current Status - June 2008

We are now three years into the study and great progress has been made with both ape species. Two research camps have now been set up some 10km apart, one bordering the ocean and the other bordering the large Iguela lagoon. The study site is comprised of the 80km² area between and around these two camps, which includes primary and secondary forest; swamp and savannah.

We estimate that there are 8 groups of gorillas and 3 communities of chimpanzees within this zone. Recent efforts have focused on 2 large groups of gorillas near the lagoon and a healthy sized community of chimpanzees closer to the ocean.

Our team includes 3 ex-patriot researchers, 3 ecoguides and 6 pygmy trackers. The trackers are a vital part of the gorilla habituation process, as they have the skills to follow the trail of gorillas in places where no signs are visible to most human eyes.

In parallel with the habituation, the MPI team has been conducting a study of food availability, specifically phenology studies (variation in fruiting patterns) and vegetation transects on tree and plant studies eaten by the gorillas and chimpanzees. 9080 trees were measured in the vegetation study and 170 different species identified. For the phenology study, 483 trees from 50 species are monitored on a monthly basis for presence of fruit / flowers / new leaves. This allows researchers to understand the availability and abundance of fruiting species, and thus assists them in predicting the movements of the apes in relation to the current distribution of resources.

Gorilla Habituation

In June 2007 we set up a second research camp (Yatouga) beside the Iguela lagoon approximately 9km northeast of our original camp site (Ozouga). The previous year we had explored this area and found there to be a much higher density of gorillas using the forest here than along the coast. Since the construction of this camp (and in parallel with the increase in pygmy trackers), the frequency of gorilla contacts has increased significantly.

The area is characterised by multiple lowland swamps, and this makes systematic tracking of the gorillas much easier. As a result, we are often able to track the same group for many days on end without losing them, which has helped us a great deal in establishing territory size and ranging patterns for the different groups.

Two large groups of gorillas (Achilles and Indegho Groups) are the primary users of these lagoon-fed swamps, and so habituation efforts for have been focused on contacting them. Visual sightings and nest site data suggest there are between 13 – 15 gorillas in each of these groups. Both groups have reacted well to observers, but a combination of larger group size and better location have made the Indegho gorillas a more favourable target for habituation and they are the main focus of our habituation efforts.

This increase in contacts has brought about a change in the behaviour of the gorillas towards the researchers. Whilst the females and juveniles are still be shy of being within visibility of observers, the silverback frequently stays at close proximity (30-40 m away) for prolonged periods of time. We advance until the silverback barks to warn us that we are too close, at which point we stop and remain motionless for 10 minutes. We then begin the advancing process again until the male barks and so it continues. The rationale is that this allows the gorillas to understand that we respect the distance with which they are comfortable in our presence, and it should result in a quicker increase in their level of trust for humans.

The gorillas have also stopped fleeing for long distances following a contact with us. When they decide to leave a contact, often they will only move 100-200m away before stopping to feed again. This is a very important step in the habituation process, as it is evidence of an increased acceptance of human presence.

Habituating gorillas is a slow process of gaining their trust and acceptance of humans at close proximity. We anticipate that it will take another 2-3 years before the group is habituated fully and tourism can begin.

Chimpanzee Habituation

Chimpanzee habituation is very different from gorilla habituation, because chimpanzees do not leave enough trail signs for systematic tracking to be a possibility because they weigh less. Chimpanzees have a fission-fusion community structure, which means that they are not in constant contact with one another and often forage in small parties or even alone. In order to keep abreast of the movements of the rest of the community (who may be over 1km away), chimpanzees use loud vocalisations and drumming on large tree buttresses as a means of communicating with the other members of their group. They are most vocal early in the morning and late in the afternoon, and researchers are able to take advantage of this fact for contacting them.

During the day they also frequently vocalise for many reasons: the arrival of another member of the community into a feeding party, excitement at the discovery of a heavily fruiting tree; or a dispute between 2 or more individuals over females, food, or dominance. While these vocalizations are advantageous because they allow researchers to sit quietly in an area of the forest where chimpanzees were seen the day before and wait for them to vocalise, it is also disadvantageous if the chimpanzees choose not to call all. Otherwise, researchers walk slowly through the forest looking for fruiting trees where the chimpanzees may be feeding.

Once we established that there were several chimpanzee communities within the study area, our habituation efforts began to focus on the “Rekambo” community of chimpanzees, found in the northwest of the research zone. Significant advances have been made with identification of these chimpanzees, and there are thought to be at least 11 adult males in the group. Our impression is that there are about 40-50 individuals in the community.

While habituation is a slow process the project continues to make significant advances, and we hope that in two to three years these apes may be comfortable enough with human presence to allow the first visitors into their special world.