Class: Mammalia (Mammals)
Length: 2.3 to 3 feet (70 to 90 centimeters) from head to rump
Weight: 55 to 110 pounds (25 to 50 kilograms) in the wild; 66 to 135 pounds (30 to 61 kilograms) in zoos
Life span: unknown in the wild; over 50 years in zoos
Gestation: about 8 months
Number of young at birth: usually 1, rarely 2
Size at birth: 2.8 pounds (1.3 kilograms)
Age of maturity: 8 to 9 years
Conservation status: endangered
Bonobos are much less fearful of water
than chimps, even fishing for shrimp with their hands.
The San Diego Zoo’s most famous pair of bonobos, Kakowet and Linda, were together for 18 years and produced 10 offspring together.
Bonobos were not formally identified as a species by scientists until 1933. Before that, they were thought to be another type of common chimp. They are still the least understood of the great apes.
In the wild, bonobos usually can get most of their liquid from fruits.
• The San Diego Zoo was the first zoo in the United States to welcome a baby bonobo.
Mammals: Bonobo (Pygmy Chimp)
Bonobos or pygmy chimps?
Bonobos are members of the great ape family, along with gorillas, orangutans, and chimpanzees. Earlier scientists thought the bonobo Pan paniscus was just a smaller version of the common chimpanzee Pan troglodytes and so the term “pygmy chimpanzee” was used. But don’t be fooled! Bonobos and chimps are really quite different—you just need to know what to look for.
Bonobos versus chimpanzees
Size— Chimps and bonobos are about the
same size, but bonobos are more slender and have
smaller heads and smaller ears.
Food— Chimpanzees eat plant material as well as monkeys and other mammals when they have the chance. Bonobos eat mainly leaves, stems, fruits, worms, insects, and sometimes small fish.
Location— Bonobos are found only in a small part of one country in Africa, the Democratic Republic of Congo (formerly Zaire). The four subspecies of “common” chimps range from western to central Africa.
Getting Along— When trouble comes between common chimps, they often fight it out. They are also very protective of their territory and will kill chimps from another group, called a troop, if they try to move in. Bonobos don’t seem to have established territories, and they tend to handle any squabbles or tension by using different sexual behaviors instead of aggression.
Looks— Bonobos can walk upright more easily than common chimps can. They also keep their white rump patch for life, while the patch darkens with age in chimps. And bonobos have hair on their head that parts right down the middle!
In bonobo society, the females take charge and keep lifelong bonds with their sons. When a daughter is old enough, she must leave the troop and find another one to join. She will breed with all the males in the new group, and she gains permanent membership when she gives birth. Adult females form strong bonds with each other. The female-led troops tend to be relatively peaceful, and bonobos seem to be sensitive to each other’s needs.
Infants are born almost helpless and must be carried everywhere by their mothers for the first two years. A youngster stays close to its mother for several years while it grows and learns how to be a part of bonobo society. Bonobos use touch to give reassurance and comfort to each other. They form close relationships with other members of the troop, even after they are grown. Although bonobos can reach their sexual maturity at 6 to 8 years of age, the females don’t usually have their first baby until they are about 13 years old.
Playing is a part of growing up, as the young bonobos gain independence and test their skills against each other. The youngsters play some of the same games you might play, such as King of the Mountain, where one chimp parades around on top of a hill or rock while the others try to pull him or her down, and Blindman’s Bluff, where young bonobos cover their eyes with their hands and run around chasing each other!
Food for all
Can you imagine living in an all-you-can-eat salad bar? When it comes to finding food, bonobos have it pretty easy in their rain forest home. They are nimble climbers and can swing from tree to tree searching for tasty fruit. Bonobos forage for food during the day in small groups, often sharing the food they’ve found, then gather together in larger groups to build their sleeping nests. These clever apes have been observed sponging water out of tree trunks with moss, fashioning a rain hat out of leaves, and shaping a twig to use as a toothpick. Bonobos also spend hours hunting for earthworms to snack on—a rain forest candy
At the San Diego Zoo, we feed the bonobos a variety of fruits and veggies: bananas, apples, oranges, grapes, turnips, carrots, yams, spinach, and broccoli, as well as leafy clippings from ficus, honeysuckle, hibiscus, and sugarcane, and leaf eater biscuits. For treats, they are offered popcorn, sugar-free cereals, nuts, and seeds.
Nests aren’t just for the birds!
Bonobos use leaves and twigs to build sturdy nests in the forks of trees each evening. By all sleeping in the same area they can help each other look out for predators such as leopards and snakes. They can also keep track of each other. Adult bonobos sometimes share a nest, which is a unique behavior among the great apes.
Who’s the smartest of them all?
Some scientists believe that bonobos are the most intelligent of the primates (other than humans, of course!). Maybe that’s because they share many of our human behaviors, such as teaching their young social skills, using tools to get food, and working together for the good of the entire troop. Scientists have taught a few bonobos, housed in labs, how to communicate with humans by using symbols that represent words on a board. They can understand spoken words and reply to questions or ask for things by pointing to symbols. Bonobos even laugh when they are tickling each other or playing together, and they do other things that may remind you of some people you know!
Bonobos in trouble
Sadly, there are few bonobos left in the wild and so they are considered the most endangered of the great apes. Humans continue to move into bonobo habitat, hunting these amazing apes for food and selling their babies into the pet trade. Commercial logging operations create new roads to harvest timber, giving people easier access to hunt or capture many rain forest species. There are also few bonobos in zoos. The San Diego Zoo and the San Diego Zoo Safari Park have successfully bred and maintained these intelligent and curious apes since 1960, and we continue to fund conservation efforts for them in central Africa.