Tales from Africa: 10 years in Gombe

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Lecture on 14 October 2018

By Heather Pong Yen Ting

In the fifth and final session of the JGIS Lecture Series on 14 October 2018, we were proud to have with us Dr Deus Myungu, the Director of Chimpanzee Research at the Gombe Stream Research Center. Gombe National Park was where Dr Jane Goodall conducted her breakthrough research on chimpanzees. The chimpanzee study, started by Dr Goodall in 1960, running to the present day, is the longest-running project there. Since then, the centre has also expanded its research to include other primates found in Gombe.

There are eight different primate species found in Gombe, and Dr Deus gave an overview of the species and some of the research studies on them. One of the recent significant findings of these projects was the observation of the mating of two of these species, the red-tailed monkeys and the blue monkeys. They had produced hybrid offspring, who in turn had successfully mated with one another and with non-hybrid individuals in the park. Consequently, this discovery challenges the notion of what a species is.

Following this, Dr Deus spoke about the main subject of his talk: the chimpanzees. He spoke about their social organisation in general and how they live in groups of up to 150 in a fission-fusion system. Unlike other primates that also form groups, the entire chimpanzee community does not troop together. Males stay in their natal communities and are involved in territorial defence, while females might disperse to join other groups.

To study the chimpanzees, field assistants chose one individual to follow every day, which they tracked for 12-14 hours a day. With the use of field maps previously, and now with the help of GPS technology, they made a record of the location, type of food eaten, who the subject interacted with, and what behaviour it was engaging in. The recording was done every 15 minutes. Over time, conclusions could be drawn about where a certain individual preferred to spend its time and who it socialised with.

The mother-infant study – a research topic that originated from Dr Goodall – made use of the long-term data available to understand how females’ maternal styles influence the survival and success of their young. The high-ranking female Fifi, who saw three of her five boys rise to become alpha male, was a case in point. Was the success of her offspring attributed to the way Fifi brought up her boys, or were there some other external factors at work? By comparing a mother’s rank, her style of mothering and the consequent level of success attained by her young, the study seeks to confirm if there is indeed correlation between these factors.

Another study was conducted that drew upon long-term data to piece together the bigger picture. This was the project on female settlement patterns. The female chimpanzees at Gombe can be divided into those which transferred from their natal community at adolescence and those which did not. Transfer carries cost with it: both loss of protection from the natal group and potential violence from females of the new group. The study involved detailed behavioural observations of adolescent females which were likely to transfer to another community. These observations were conducted in order to understand the factors that influenced their decision to leave their family. Chimpanzees are territorial, and a lot of their behaviour is driven by distribution of food. One of the findings was that chimpanzees breed with genetically dissimilar mates. It had been discovered that females also have a hierarchy. High rank improves reproductive success for both males and females. In general, mothers also tend to socialise more with their sons than their daughters. Research findings could potentially help shed light on the behaviour of not only chimpanzee, but also human behaviour.

A third significant study was conducted on the effects of Simian Immunodeficiency Virus (SIV) in chimpanzees. Though previously thought to have little impact on the chimpanzees, studies have shown that SIV is in fact killing them. SIV-afflicted chimpanzees are less likely to live longer than those that do not – results show they have less chance of survival past 5 to 8 years. As it turns out, the effects of SIV and Human Immunodeficiency Virus (HIV) might be similar.

Dr Deus also shared that disease is a major cause of mortality among chimpanzees. Besides the SIV, they are also susceptible to diseases like polio, which killed 30% of the population during a recent outbreak. It takes 15 years to replace an adult that passes on, so battling diseases is one of the main challenges.

The team at Gombe have an approach called Ecosystem Health Monitoring, which they implement through the use of health checksheets, other non-invasive methods and post-mortems. On a daily basis, the team looks out for physical injury on the chimpanzees they are tracking. Other physical signs like types of faeces, body condition and coughing, early warning symptoms of disease, are recorded the checksheets. Faecal samples are collected and checked for parasite loads. They are also analysed to determine and monitor the stress level in individuals. Post-mortems are done opportunistically when dead chimpanzees are found. The veterinarians on the team collect tissue samples and run analyses to check for pathogens.

Visitors to the park are also required to adhere to chimpanzee observation guidelines like the distance rule – everyone is to keep at least a 7-metre distance from chimps. Whoever is coughing is not allowed in the park to reduce the risk of disease transmission. A maximum of five visitors are allowed with a guide, to avoid adversely influencing the behaviour of the chimpanzees. If, for example, a female joined the community from another community, she will try to get used to her new group. At the same time, she may become nervous due to the presence of too big a crowd. Male chimpanzees may misinterpret this as rejection of the group and vent their frustration on the female.

Dr Deus carried on to give an overview of conservation efforts by JGIS and other NGOs in the region. There are 2000 chimpanzees in Tanzania but only the 90 in Gombe are well protected. Outside of the national park, protection is not as good. A lot of habitat destruction is taking place at an alarming rate, with large herds of cattle moving into the area. Work is underway to extend the perimeters of protection to the outskirts of the park. In a survey involving local people, the team was able to spot some chimpanzee nests and there may be some 20 individuals living in that area. Work is underway to set it aside as a village forest research station. Most of the people living in there are from a neighbouring country which is not politically stable.

JGIS is working with NGOs to talk to people about land use planning, and starting initiatives like sustainable coffee farms. They work with local communities to educate them on conservation and how conservation is good not only for animals, but also for them. The Roots & Shoots programme plays an important role in engaging youths so they can make better decisions on the methods of conserving the environment. The team has seen good progress in the development of a national chimpanzee action plan to implement policies to guide chimpanzee conservation in Tanzania. To combat the threats that chimpanzees face, stakeholders need to work together to ensure their survivability in the wild.

The JGIS Lecture Series was made possible with the generous support of the Shirin Fozdar Foundation and the National Parks Board.