Field guide to chimpanzees
Chimpanzees are our closest living relative and share many of our characteristics, says primatologist Sonya Hill, as she introduces us to this charismatic ape
Chimpanzees were something of a mystery until pioneering research into their wild behaviour was begun in the 1960s by a young, untrained but passionate Englishwoman, called Jane Goodall. She was sent to study chimpanzees to shed light on our own evolutionary past in what has become Gombe National Park in Tanzania. Jane discovered chimpanzees to be intelligent makers and users of tools, and to have richly complex cultural, social and emotional lives. She redefined what it means to be human, and helped change the way we think about animals.
Similarities between chimpanzees and humans also mean that these African apes are exploited by humans, whether in the “entertainment” industries, biomedical research, or pet trade. But, it is also their similarities to us that have led to a movement to protect chimpanzees. After all, how can we let our closest living relative go extinct? Responsible wildlife tourism and community centred conservation can help ensure that species like the chimpanzee have a secure future. In protecting a flagship species like chimpanzees, we can also protect the many other plant and animal species that share their habitats.
Today, research into wild chimpanzees takes place at many sites across Africa. Through these studies, we continue to learn more about chimpanzee biology and behaviour, whilst at the same time racing against the conservation clock in efforts to save them.
Types of chimpanzees
The International Union for Conservation of Nature (IUCN) currently recognises four subspecies of the common chimpanzee: the West African (Pan troglodytes verus); the Nigeria-Cameroon (P. t. ellioti); the Central (P. t. troglodytes); and the Eastern (P. t. schweinfurthii).
Where chimpanzees are found
Chimpanzees are the most abundant and widespread of the non-human apes, (gorilla, chimpanzee, orangutan, bonobo and gibbon). They are found in both moist and dry forests, and gallery forests extending into savannah woodlands. Their distribution ranges from west to east across Equatorial Africa, but their range is patchy due to loss of habitat. Pan troglodytes verus is found in West Africa, from Senegal to Nigeria. P. t. ellioti is found only in Nigeria and Cameroon, north of the Sanaga River, whereas the Central chimpanzee, P. t. troglodytes, ranges from south of the Sanaga River in Cameroon to the Congo River/Ubangi River in the Democratic Republic of Congo. The Eastern chimpanzee, P. t. schweinfurthii ranges from the Ubangi River/Congo River in Central African Republic and the Democratic Republic of the Congo, to western Uganda, Rwanda and western Tanzania. There are also small, “relict” populations of the Eastern chimpanzee in Burundi and south-eastern Sudan.
Chimpanzee physical characteristics
Many people are familiar with how chimpanzees look, but they can confuse them with other great apes. Chimpanzees have black hair (not fur!) covering most of their bodies, with bare skin on the palms of their hands and feet as well as their faces and ears, which can vary in colour from pink to black.
Like humans, chimpanzees have flat faces with forward-facing eyes and relatively small noses, and they might have some whiskers on their chins. Also like us, they rely more on vision than on their sense of smell. Chimpanzees’ arms are longer than their legs and they have opposable thumbs and big toes, enabling them to have a precision grip. All of their limbs are very flexible, to aid movement through their habitats.
Infants have very pale skin and a white tuft of hair on their bottoms, which disappears as they grow up. Adult males are larger and heavier than females, weighing on average 40-60kg and measuring up to about 1.5m tall when standing upright. Females, by comparison, weigh about 32-47kg and standing about 1m tall. At birth, chimpanzees weigh up to about 2kg. They typically live for about 40-50 years in the wild.
What chimpanzees eat
Chimpanzees eat an omnivorous diet, which varies by seasonal availability and population. About 50 per cent of their food is comprised of fruit, although leaves, bark, nuts, blossoms, stems and insects are also eaten.
Medium-sized mammals, such as monkeys, antelope and bush pigs, also form a small, but important, component of the diet of many populations. These mammals are hunted cooperatively by male chimpanzees, and a portion of the kill is typically shared with other group members in response to a variety of begging behaviours. Most of the captured animal is eaten, including the brain. Another interesting observation is that chimpanzees sometimes deliberately eat medicinal plants (e.g. aspilia leaves) and minerals, which are believed to relieve stomach pains or reduce internal parasites.
When Jane Goodall began her chimpanzee studies in 1960, very little was known about their behaviour. Today, ongoing research at Gombe and a range of other African field sites show that chimpanzees are even more fascinating and complex than was originally thought. This is part of the appeal of viewing chimpanzees in the wild – it is a truly magical experience to see our closest living relatives in their natural habitats.
Cultural traditions develop in different groups, and are transmitted between individuals through learned behaviour. Some behaviours are commonly seen species-wide, even if they can vary in precise form between groups. These include grooming, hunting, nest building, foraging and communication.
Like humans, chimpanzees are highly sociable beings. Social interactions are essential for their development, learning and overall well-being. They live in groups called communities, which can comprise over 100 individuals. Their social structure is known as “fission-fusion”, whereby the main community divides up frequently into smaller subgroups. The membership of these small groups is always changing as individuals go off on their own, or join other subgroups.
At times, many of a community's members come together in large excited gatherings, usually when fruit is available in one part of the range, or when a popular female is sexually receptive. Family bonds, and bonds between some other chimpanzees, are very strong and usually last a lifetime, although individuals may occasionally switch to a different community. Mother-daughter bonds can be the strongest.
Contact is maintained between members of the scattered subgroups by means of a distance call, known as the “pant hoot”, which both males and females use. The pant hoot is probably the most well-known chimpanzee vocalisation, and begins with a series of breathy, low-pitched hoots that get quicker and higher in pitch until they reach a loud climax. It is also used to express excitement, such as arriving at fruiting trees, or as a greeting when meeting up with other members of the community. You will never forget hearing your first pant hoot!
Females leave their birth group on maturity and spend most of their time alone, with their dependent offspring. Males usually remain in their natal groups and cooperate in defending their community’s range, spending long periods of time in proximity to other males. They sometimes form coalitions to support each other during conflicts with other groups.
There is a strong male hierarchy within a community, following a more or less linear pattern, with the top-ranking male that scientists refer to as the “alpha”. All adult males dominate the females, but females have their own hierarchy as well, albeit more complex than the males’. Females (and lower ranking males) can help determine whether an alpha male stays at the top or not – he must win and maintain the support of allies to maintain his position of power, strengthened through social interactions and grooming. An over-bullish male might find he loses that support and gets overthrown by another, more popular male.
Alpha males are typically in their twenties, and factors that can determine dominance and social status include their physical fitness, aggressiveness, fighting skills, ability to form coalitions, intelligence, and other personality traits.
Chimpanzees live in multi-male, multi-female communities and can best be described as promiscuous! They reach sexual maturity between the ages of 10 and 13, but females are unlikely to conceive for the first couple of years. When they are in oestrus, females exhibit a characteristically large pink bottom, known as a sexual swelling, which signals that they are sexually receptive, and it can attract a lot of attention.
Females typically reproduce every five years or so, but a high rate of infant mortality means that a mother might raise no more than three offspring to full maturity during her lifetime. Gestation is around eight months, not too dissimilar to the length of a human pregnancy. Young chimpanzees rely upon their mothers for care and, ultimately, survival, remaining dependent on them until about five years of age. The weaning period can be quite traumatic for a young chimp, especially if a younger sibling comes on the scene. Tantrums are not uncommon!
Threats to chimpanzees' survival
All four subspecies of chimpanzee are classified as Endangered. Major threats are human-related and are primarily the result of habitat destruction and degradation, poaching and disease.
Deforestation across western and central Africa has had a major impact on reducing the natural habitat of chimpanzees, and the rapid population expansion continues to place a heavy pressure on conversion of forest to agricultural land for people. Logging, and mining for gas, oil, and ‘coltan’ (columbite-tantalite, a metallic ore found in electronic devices such as mobile phones), also put huge pressure on the forest, and remote areas which are made more accessible through road construction. This degrades chimpanzee habitat and creates forest fragments or “islands” with barren land in between.
These activities also open up opportunities for illegal poaching in areas that were previously very remote. Chimpanzees have low population densities and are slow to reproduce, so commercial hunting for the illegal bushmeat trade has a devastating impact on their populations. Some chimpanzees are also maimed or killed unintentionally, when they find themselves caught in hunters’ snares that were set for other animals.
There is little meat on a baby chimpanzee, so these youngsters, traumatised from the experience of capture, often end up in the illegal pet trade as a by-product of the bushmeat crisis – if they survive it at all. It is estimated that for every infant captured, another 10 or so chimpanzees in its community will have been killed. The figures are staggering and devastating to chimpanzee conservation. Surviving infants might be confiscated by successful law enforcement and can find themselves in a sanctuary, such as one of those accredited by the Pan African Sanctuary Alliance (www.pasaprimates.org). Here, efforts are made to nurse traumatised orphans back to health and to rehabilitate them, and they have to learn the skills they need in order to survive as adults.
Infectious disease is another major cause of death in wild chimpanzees. Because humans and chimpanzees are so closely related, they can catch many of the same diseases that we can, such as the Ebola virus, respiratory illnesses, polio, and so on. Transmission can occur through close proximity of people and chimpanzees, and so research and tourism activities have to be managed very carefully. Expansion of human populations into chimpanzee habitat is also problematic.
Where to see chimpanzees in the wild
Gombe National Park
Gombe is a magical gem on the shores of Lake Tanganyika. To view chimpanzees here is to view them “where it all began”, as it is home to Dr Jane Goodall DBE’s pioneering research. Gombe is the smallest of Tanzania’s National Parks, and is home to about 100 chimpanzees. In searching for them, you can also visit “Jane’s peak” and “Jane’s waterfall”, made famous in her popular writings about Gombe. You can also hike through the beautiful forest alongside the glittering lake with its beachcomber olive baboons. Gombe is reached by boat in a few hours from Kigoma Town. The boat trip itself offers the opportunity to try to spot a variety of 1,000 or so bird species in the region, and to see the beauty of the steep slopes and traditional beachside fishing villages. The lakefront beach at Gombe offers an opportunity for relaxing and swimming after your trek.
Mahale Mountains National Park
Further south from Gombe, also along the shores of Lake Tanganyika, is Mahale Mountains National Park. Mahale is home to a population of about 900 chimpanzees, which have been studied since the 1960s by Japanese researchers. Like Gombe, visitors to Mahale can also view a range of other wildlife species, including baboons, red colobus monkeys and forest birds, and enjoy the beauty of the landscape and the lake. It is another stunning place to view chimpanzees in their natural habitat.
Kibale National Park
Uganda offers several excellent places for visits to see wild chimpanzees. Kibale National Park, in the west, ranges from wet tropical forest to woodland and This Park hosts a famous research site with a population of about 1,450 chimpanzees, and offers a variety of wildlife viewing, including butterflies, elephants, hundreds of species of birds, and numerous other primates. The diversity and density of primates in Kibale is the highest in Africa.
Kibale is adjacent to Queen Elizabeth National Park, which is Uganda’s most popular tourist destination and home to an unusual population of chimpanzees at Kyambura Gorge. The gorge is a kind of “underground” rainforest, surrounded by savannah above ground. It feels rather mysterious, as if you are stepping back in time. No sighting of wild chimpanzees can ever be guaranteed anywhere, and this disclaimer is even more appropriate for the Kyambura chimpanzees. The gorge is home to only about 16 apes, who are “trapped” in this richly biodiverse “island”. The chimpanzees have no way of knowing just how far the unsuitable savannah habitat spans around it, so it would be a risky option for them to venture too far outside the gorge. For visitors, this adds to the mystery and adventure of trying to track them and catch a glimpse, listening out for their calls. It is also a sobering reminder of the effects of forest degradation on chimpanzees.
Budongo Forest Reserve
Budongo Forest Reserve, close to Murchison Falls National Park, is home to a population of about 600 chimpanzees, of which about 60 are the subjects of long-term research. Budongo is a “managed forest” with some timber extraction allowed, and it offers visitors an insight into human-wildlife conflicts, and how these are mitigated. Other animal species at Budongo include various monkeys, duikers, bush pigs, and over 350 species of birds. It is even possible to make a day trip to Budongo from Kampala, although longer visits are recommended.
Most of the chimpanzee safari tours are in Uganda and Tanzania. It is a privilege to observe chimpanzees in their natural habitat, but viewings have to be managed carefully to avoid disease transmission, and disturbance to their daily lives and social structures.
Responsible tourism is key to conservation efforts, providing habitat protection, and sustainable livelihoods for local people. It is important to respect the environment on any wildlife trip, and it is no different when watching chimpanzees. There will be rules at each field site which must be obeyed, such as miminum distances to be maintained between visitors and the chimpanzees (usually at least 10m), and disallowing unwell people to visit.
Keeping a quiet and submissive demeanour is imperative, as chimpanzees are potentially dangerous wild animals. In choosing a travel company, it is important to enquire about their ethical policies, as well as any community-centred conservation initiatives that they support. This way, you can be confident that your visit to the chimpanzees will be having the right kind of impact, and you should come away inspired to help protect the chimpanzee.
When to VIEW CHIMPANZEES
You can view chimpanzees all year round, but the ‘cooler’ dry season in June-October is the most popular time to see them in East Africa. The weather is likely to be pleasantly hot and sunny with little rain, so forest paths are less slippery (though the air might be more dusty), and mosquitoes and malaria are less of a concern. That said, visiting in the wet season, November to May, has its benefits, too, such as an abundance of butterflies and migratory birds, cleaner air, and waterfalls at their most impressive, though the conditions are hot and humid, and there is a higher risk of diseases such as malaria. When planning your visit, you’re also advised to check if there are any logistical restrictions, such as accommodation closures in the low season around April-May in the ‘long rains’.
The Jane Goodall Institute
Founded in 1977, the Jane Goodall Institute continues Dr Goodall’s pioneering research on chimpanzee behaviour – research which transformed scientific perceptions of the relationship between humans and other animals. Today, the Institute is a global leader in the effort to protect chimpanzees and their habitats. It also is widely recognised for establishing innovative community-centred conservation and development programmes in Africa such as Jane Goodall’s Roots & Shoots, the global environmental and humanitarian youth programme, which has groups in more than 120 countries. For more information, please visit www.janegoodall.org.uk, www.janegoodall.org and www.rootsnshoots.org.uk