Inroads to Animal Conservation
The Jane Goodall Institute
“A chimpanzee being held in a Brazzaville zoo was emaciated, hairless, and half blind because he was not receiving adequate nutrition. I put together a group of expatriates, employed some keepers, and built him a small patio in an attempt to improve his life. He put on weight, grew hair, and regained his eyesight. He was thrilled to have branches that allowed him to nibble the leaves and make nests. And for the first time since 1944, when he was put in his cage, he was able to go outside and feel the warmth of the sun. He is now one of the oldest chimpanzees in captivity. I do not know how he survived all those years without proper food. Some indomitable spirit in him kept him alive.”
Louis Leakey believed that he could learn more about the probable behavior of our earliest Stone Age ancestors from a study of the chimpanzees in the wild. He argued that behavior common to modern chimpanzees and humans was probably also present in a common ancestor millions of years ago. Leakey is well vindicated, because most human evolution textbooks describe the chimpanzee, and specifically the Gombe chimpanzee, behavior in some measure.
Scientific attitude has changed towards these relatives of ours, the nonhuman primates. In the 1960s, the strict ethnological science of Europe did not believe that animals had personalities. Only humans had personalities. Animals were presumed to have no ability for rational thought and problem solving. The worst sin of anthropomorphism was that animals be credited with any kind of emotion.
It is fascinating that since 1960, attitudes have softened and there is no longer a passion for reductionism. People are much more prepared to look at the societies of nonhuman animals and see complexity and individuality. Discussing emotions is usually acceptable if it is done in the right way. The animal mind is now a popular study of many graduate students.
CHARACTERISTICS OF THE GOMBE CHIMPANZEES
The Gombe stream is a 30-square-mile area. It stretches for 10 miles along the shore of Lake Tanganyika, a steep, hilly country, falling down forested slopes from the Rift Escarpment. That area is home to approximately 100 chimpanzees, who have provided us with a wealth of information about primate behavior, including feeding behavior and diet selection, among many others.
The main study community of Gombe consists of some 50 individuals — adults, adolescents, and infants. Male chimpanzees are more overtly aggressive and fight more than females. But because they are ordered in a dominance hierarchy, where males know their positions relative to each other and are dominant to all females, disputes within a community can often be settled by a threatening posture or gesture. A male will bristle his hair, bunch his lips in a ferocious scowl, swagger, brandish sticks and so on.
After some kind of aggression, the victim even though fearful of the more dominant aggressor is likely to approach with some kind of submissive gesture, such as a crouch. In response, the aggressor is likely to reach out with a reassurance behavior such as patting, touching, or even kissing and embracing. And so, social harmony is quickly restored to the group, even after quite serious aggression.
Nonverbal communication patterns of the chimpanzees almost uncannily resemble some human postures and gestures and tend to occur in the same type of context. A nervous female may reach her hand out for reassurance and the male may gently calm her by patting her hand. An adult male may be greeted with a kiss when he joins a young female. Friendly physical contact in chimpanzee society maintains friendships and improves bad relationships. Males will spend long hours peacefully grooming each other, but if two chimpanzees do not like each other, they will not groom. Many of these patterns are inborn; but a young chimpanzee raised in social isolation although he may use these postures and gestures, will do so in inappropriate contexts.
A wild female chimpanzee gives birth approximately every 5 years and usually has her first baby when she is between 11 and 13 years of age. Age of
first birth is directly related to body weight, which may be correlated with nutrition. Young chimpanzees in captivity, consistently fed a nutritious diet, can have babies as young as 7 or even 6 years of age. Usually one baby is born, but twins do occur.
Childhood is a time of much activity and a great deal of that activity is play. Young chimpanzees are very well tolerated by other non-related adults in the community. Infants up to 4 years old can take great liberties with their elders. As they move toward adolescence, they become more cautious, particularly in their dealings with adult high-ranking males. Young males must be especially cautious.
NATURAL DIET AND FEEDING BEHAVIOR
Food is plentiful for most of the year in this part of Africa. Chimpanzees are omnivores but the greatest proportion of the wild chimpanzee diet is fruits, which change in type, quantity, and nutritional quality according to the season. Many of the big forest trees have a pattern of fruiting every second year. But sometimes trees fail to fruit and then the chimpanzees lose weight apparently due to decreased food supply.
Chimpanzees in the wild spend a certain amount of time feeding on one type of food, and then, they will usually move on and feed on something else. The variety of their diet is impressive — over 600 different foods are eaten in some areas. As well as fruit, they eat leaves, nuts, shoots, stems, bark, blossoms, seeds, insects, bird eggs and meat (Figures 1a,b). Based on observations of wild chimpanzees, it is clearly preferable for the diets of captive animals to be varied, so they do not get bored with their food.
Chimpanzees are good hunters, and, after a successful kill, other chimpanzees gather around the hunter and beg for a share. Sharing may or may not take place depending on the personality of the hunter, the amount of meat and his relationship with those who are begging. Usually after a fairly big animal has been killed, high-ranking males rush in and come away with some portion of the carcass.
Although meat is a highly preferred food and “kills” stir up excitement, meat comprises only 2 percent of the chimpanzee’s natural diet. Primates are the preferred and most frequently caught prey for chimpanzees across Africa. Colobus monkeys are the most frequently killed at Gombe. Young pigs and young bush buck are also hunted.
Insects are eaten much more frequently, and termites are popular at Gombe. Termites that fly off from the nest to form new colonies are caught by hand. At other times, chimpanzees will scrape open a tunnel into a termite mound and use a piece of grass to draw them out. Sometimes they strip leaves from a twig for this purpose. It was these observations, made in 1960 because that prompted the National Geographic Society to start funding research, at that time it was thought that only humans used and made tools. Females may “fish” for termites for up to five hours to consume the protein and lipid rich termites. Males seldom termite fish for more than an hour and do not termite fish as frequently as females. They capitalize on the termite season, when the rains begin and when every tool is likely to yield an abundance of insects.
Chimpanzees also eat army ants, which bite fiercely. They live in underground nests. A chimpanzee approaches, opens the entrance by digging in the earth with one hand. He or she then selects a long, thin and very straight stick, peels off the bark and any twigs to make a smooth tool. Then, often sitting on some branch off the ground, he pushes the stick into the nest, waits for a mass of ants to swarm up, sweeps them off into one hand, and crunches them up as fast as possible. After a few minutes, he usually runs off to slap and pick off the ants that have started biting his legs and arms.
Different feeding and tool-using traditions are found among chimps in different parts of Africa. Even if a certain food is freely available in two areas, it may be eaten in one place and not another. It seems that those feeding, tool-using and other traditions may be passed from one generation to the next by observation, imitation, and practice. Infant chimps are intensely curious, and watch closely the foods eaten, the manner of eating them, and tools that are used for acquiring food (or any other purpose). They often then perform — or try to perform — the actions they watched. Behaviors passed on in this way may be described as primitive cultures.
Cannibalism has been recorded in chimpanzees in Tanzania and Uganda. Occasionally adult males will kill and partially eat the infant of a female of a neighboring social group. At Gombe, one mother infant pair during a 4-year period, were seen to kill and eat five newborn infants of females of their own group. Five other newborns disappeared and it is thought that they suffered the same fate. Since then, two different females have been seen hunting newborns on two different occasions: both times they failed. This behavior is not understood.
In 1960, the eastern shore of Lake Tanganyika, some 300 miles long, comprised forested hills dropping from the Rift Escarpment to the lake. From the Burundi border in the north to the southernmost part of the Mahali National Park in the south, there were some 100 miles of chimp habitat. If one climbed to the top of the rift and looked eastward, again there were forested slopes, with just a few small villages, as far as you could see. Today, cultivated fields press up to the boundaries of the tiny 30-square-mile Gombe national park on three sides: the western boundary runs along the lake shore. Outside the park there has been almost total deforestation. With the tree cover gone, the soil has become infertile. Moreover, during the rainy season the thin layer of top soil erodes down the rocky hillsides into the valleys and the lake, where it silts up the fish breeding ground. Some places that were forested ten years ago now look like a desert, and the chimpanzees have long since gone. Only about 100 Gombe chimpanzees remain, isolated in their patch of forest, and doomed because their gene pool is not big enough to be viable.
The situation has deteriorated to this extent partly because of population growth. But this troubled part of Africa also has a terrible refugee problem.
Refugees have poured in from Burundi, 20 miles to the north, and from the Democratic Republic of Congo in the west. The people living here are beginning to face starvation because they are far too poor to purchase food from other areas where it is more suitable to grow. They cannot move as they would have done previously, because the land is already occupied unless they move south, which some of them are doing.
It is difficult to protect the precious 30 square miles of Gombe when the people around the park are starving. Conflict between humans and wild animals is destroying much of the natural habitat across Africa and other parts of the developing world. Even national parks and reserves in the developed world are not safe from the greed of those who find oil and other minerals under the surface of the supposedly sacred land.
A conservation and education program has been started that focuses on tree nurseries and agroforestry in 30 villages around Gombe. A team of Tanzanians that speak local dialects introduce conservation and education concepts. A group of women are employed to teach village women about farming methods more suitable to the terrain. Trees that give instant profit, like fruit trees and fast growing trees for firewood, are grown. Indigenous plants are reintroduced and attempts to control and prevent erosion are made.
Improving womens’ self esteem through education and by raising money for the family eventually leads to decreased family size. Primary health care, especially for women and children, is also part of the program because women cannot plan a family unless they expect their children to live. Family planning and AIDS education are also included.
Many local people are employed in the park to observe the chimpanzees. They write detailed notes and use 8-mm video cameras and are proud of their work. This local pride may be why Gombe does not traditionally have poaching, while the primary threat to primates in other parts of Africa is the bush meat trade, the commercial hunting of wild animals for food.
Many chimpanzees end up in medical research laboratories because they are our closest living relatives, because their bodies are more like ours than that of any other living creature, and because they can be infected with diseases otherwise unique to us, like AIDS and hepatitis. Whether or not we think it is ethical to use them, the conditions under which most of them are maintained still need to be greatly improved. The contribution of animal nutrition to the well being of captive chimpanzees is paramount. The chimpanzee is a creature that looks out at the world around and is continually questioning, is continually fascinated. What goes on in the mind of a wild chimpanzee as he contemplates the raindrops bouncing off his hand in a storm? We will never know, but of one thing we can be sure: there is a mind and it is not that different from ours.