The Dian Fossey Gorilla Fund International's Karisoke™ Research Center is a leader in the scientific research on mountain gorillas and their habitat. Scientists and students from Africa and all over the world come to work with our researchers at Volcanoes National Park in Rwanda where we follow approximately 120 individual mountain gorillas every day- almost one third of those who survive in the Virunga mountains that straddle the border between Rwanda and the Democratic Republic of Congo (DRC). The Fund also supports research on the other subspecies of eastern gorillas, the Grauer's (eastern lowland) gorilla that is found west of the Virungas in the eastern DRC.
Overall, the mountain gorillas of the Virunga region are the most studied of any population of gorillas, as a result of our 40+ years of work in the region. In the past decade, more information on other populations of eastern gorillas, particularly those living in Bwindi Impenetrable National Park in Uganda, as well as the much more elusive western gorillas, is being gathered. As a result, scientists are finding that there are many more differences between the subspecies than originally thought, which is likely a result of their very different habitats. Data on gorillas are also obtained from accredited zoos in North America and Europe, although only one of the four subspecies-the western lowland gorilla-is found in zoos.
Mountain gorilla research
Each morning, Karisoke's trackers locate their assigned gorilla group by going to their night nest location and then following the trail of crushed vegetation left behind as the group started moving. After finding the group and recording its location using a global positioning system (GPS), the trackers find each individual in the group and record information on its general appearance and health, as well as any group composition changes due to births, deaths and immigration or emigration. Once they locate the groups, the tracker teams are joined by national and international researchers in charge of observing and collecting behavior data for our long-term gorilla research database and specific studies.
Long-term study pays off
Dian Fossey started her research in the 1960s, to learn about the mountain gorillas as individuals, as well as their feeding habitats, social interactions, ranging patterns, and relationship to their environment. The long-term studies Dian Fossey started at Karisoke™ have continued for over 40 years, including during eight years of civil war in the 1990s, with only one brief interruption. As a result, many of the Virunga mountain gorillas are very accustomed to human presence. That is why we are able to follow the same individuals every day and record their behavior in great detail.
In the 1970s and '80s, the gorilla groups we studied were small. They ranged from 6-25 individuals, including one or two silverbacks and one or two blackbacks. By 2006, the three main research gorilla groups had grown to the point where they ranged from 25 to more than 60 individuals. Each group included an average of three to six silverbacks (mature males) and four to six blackbacks (younger adult males). Pablo's group, with 65 individuals and six silverbacks by late 2006, was the largest group of any type of gorilla ever observed.
Beginning in March 2007, the groups we had studied for so long began to split up. At the same time, solitary males took advantage of the situation and established new groups. As a result, nine groups were formed from the original three. This opened up many new opportunities for our research staff to observe behaviors such as females changing groups, silverbacks striking out on their own; and changes in the leadership of groups. It also offered an unusual opportunity to observe changes in how the gorillas interact with each other as their group changes, and to compare small with large groups and single male groups with multi-male groups. In addition, two silverbacks who had each led a group for over 15 years died during 2009, leading to more changes. In fact, so much has been going on for the past few years that new field researchers were hired to help keep track of all the different groups. Such long-term data, now spanning more than the lifetime of a gorilla, provides insights into gorilla behavior that are often difficult to observe in short-term studies.
Grauer's gorilla research
Most of the Grauer's gorillas we work with have never been studied before, and we are just beginning to learn about them. Some researchers work in community-based nature reserves established over the past decade by local authorities and supported by the Dian Fossey Gorilla Fund. Because the gorillas are not yet used to humans, most of the research has been done at a distance.
The community rangers collect data on the many plants and animals in the forest, in particular large mammals such as chimpanzees, buffaloes, elephants, leopards, and okapi, as well as gorillas. They record the location of any signs of animals, such as nests, sounds and droppings, and also evidence of any human activities in the forest. The data are gathered in a central database and analyzed to provide information on of the number of gorillas and other animals in the area, how they are distributed in the landscape, what they eat, their genetic diversity (through DNA tests) and other information. They are also beginning to accustom two groups of gorillas to having human observers nearby, a process called habituation.
The Dian Fossey Gorilla Fund has recently established a new program of its own, applying the successful Karisoke™ model to study selected groups of Grauer's gorillas in the heart of their habitat, mostly outisde the boundaries of the community reserves. Thirty field staff, many of them members of the reserves, work from a central field station and four mobile satellite camps deep in the forest. Developments in this program will be posted periodically on the Fund's enews page and blog.