Tool Use, Hunting & Other Discoveries
In 1960, Jane Goodall traveled to what was then Gombe Stream Chimpanzee Reserve in the British protectorate of Tanganyika to study the behavior of the wild chimpanzees. The groundbreaking discoveries she made in Gombe became the foundation of future chimpanzee behavioral research and dramatically changed how animal behavior is studied.
Chimpanzees make and use tools in a variety of ways. Their toolmaking can also vary based on habitat and location. The typical objects turned into tools at Gombe National Park include stems, twigs, branches, leaves and rocks. Chimpanzees use these objects for many purposes, including feeding, drinking, and cleaning themselves. Sometimes they even use these objects as weapons. In other habitats and in other areas of their range, researchers have observed chimpanzees using and making tools in differing ways. For example, the chimpanzees of Tai National Park in Cote d’Ivoire crack open nuts with rocks while there is no record of the Gombe chimpanzees using rocks in this manner.
Chimpanzees use more tools for more purposes than any other creature except human beings.
Jane Goodall first observed a chimpanzee, David Greybeard, using a tool in November of 1960. She watched from a distance as David poked pieces of grass into a termite mound and then raised the grass to his mouth. After he left, Goodall approached the mound and repeated the behavior because she was not sure what David was doing. She found that the termites bit onto the grass with their jaws. David had been using the grass as a tool to “fish” for termites!
Read about recent observations on the JGI Chimpanzee Blog.
Man the Toolmaker
Soon after Goodall's initial discovery of tool use, she observed David and other chimpanzees picking up leafy twigs, stripping off the leaves, and using the stems to fish for insects. This change of a leafy twig into a tool was a major discovery. Before this, scientists thought that only humans made and used tools, and that this ability was what separated humans from other animals. This discovery caused famed anthropologist and paleontologist Dr. Louis Leakey to write this famous line in a telegram to Goodall:
Now we must redefine tool, redefine man or accept chimpanzees as human.
One of the first and most significant discoveries made by Jane Goodall was that chimpanzees hunt for and eat meat. During her first year in Gombe she observed a male chimpanzee, David Greybeard, an adult female and a juvenile eating what she realized was a young bushpig. Before this, scientists assumed chimpanzees only ate fruit and leaves.
On that first occasion, it was not clear whether the chimpanzees had caught and killed the prey, or merely come upon a carcass. A short time later, Goodall actually observed the hunting process when a group of chimpanzees attacked, killed and ate a red colobus monkey that had climbed high into a tree. The hunters covered all available escape routes while one adolescent male crept after the prey and caught it. The other males then rushed up and seized parts of the carcass.
Successful hunters typically share some portion of their kill with other group members in response to a variety of begging behaviors. Most of the captured animal is eaten, including the brain. Meat is a favorite food item among chimpanzees, but it makes up less than two percent of their overall diet.
Read about recent observations on the JGI Chimpanzee Blog!
Goodall also observed enduring, affectionate and supportive relationships between chimpanzee family members―bonds that often lasted throughout the chimpanzees' lives. Her early observations of mother-child bonds because one focus of the long-term Gombe field study. Today, researchers continue to document mother-child relationships, some 50 years later.
During their first year, infant chimpanzees are in constant physical contact with their mothers, often traveling on their mothers' backs. Around two years of age, young chimpanzees will start traveling short distances from their mothers, and will also begin moving independently. Mothers wean infants between the ages of 4 and 6 – often a very trying time for a young chimpanzee! Typically chimpanzees will become fully independent between the ages of 6 and 9, although they often maintain lifelong bonds with their mothers. Adolescent females sometimes join nearby groups for periods of time. Males stay within their group and spend their time with other males.
If a mother dies, her orphaned offspring may be unable to survive. Older siblings often adopt their orphaned brothers and sisters and sometimes chimpanzees are adopted by other members of the group that are not related to them.
When baby chimps are born, older siblings sometimes act in a jealous manner because of the loss of their mother’s attention.
Twins born in the wild are extremely rare. Since the research began more than 50 years ago, there have only been three sets of twins born in Gombe! The most famous Gombe twins, and the oldest set of chimpanzee twins in the world, are Golden and Glitter who were born to Gremlin in 1998. Want to know more about the twins? Visit their Facebook page.