copyright ©2004 by William H. Calvin

William H. Calvin

The Bonobo Page

William H. Calvin is a
 neurobiologist at the
 University of Washington
 Seattle WA 98195-1800 USA

and the author of 12 books including
A Brain for All Seasons: Human Evolution and Abrupt Climate Change (2002)
and A Brief History of the Mind: From Apes to Intellect and Beyond (2004).


Bonobo standing on shoulders

The best book around on bonobos is probably
Frans de Waal,
Bonobo: The Forgotten Ape
(University of California Press 1997)
with excellent photographs by Frans Lanting.

from deWaal and Lanting 1997 book BONOBOBonobos (the "Left Bank Chimps"), also known as pygmy chimpanzees, were the last ape species to be identified, some three centuries after the other apes were known to science. That's because they only live in one small and shrinking place, the swampy equatorial forests of the left bank of the Congo River (common chimps are the Right Bank Chimps, extending from Tanzania and Uganda all of the way to West Africa). Behaviorally, these two Pan species are our closest cousins.

If you want to see a stand-in for what human ancestors looked like, and acted like, five million years ago, go and watch a band of bonobos in a zoo (lists below).

View the BBC's excellent program (in streaming video) on the threat to the African apes from the bushmeat trade. 


Bonobos and chimps are our closest cousins among the apes. The uncommon social structure, sexual behavior and intellectual capacity of bonobos give us a unique glimpse of the roots of human nature.

Many people do not know the difference between a monkey and an ape. The six remaining ape species (gibbon, siamang, orangutan, gorilla, chimpanzee, and bonobo) all live quite close to the equator, in either Africa or southeast Asia and its offshore islands.

Apes last shared a common ancestor with the Old Worldfrom deWaal and Lanting 1997 book BONOBO Monkeys about 25 million years ago; they are tailless, have very versatile shoulder joints, and have brains about twice the size of monkeys.

Humans evolved from an ape species that existed about 5-6 million years ago, as did the common chimpanzee and the bonobo. (See my book, A Brain for All Seasons, and the San Diego Zoo bonobo page.)

Bonobo Protection Fund

Bonobos live in the wild in only one section of the Congo River basin of the Democratic Republic of Congo (ex-Zaire), unlike the common chimps which range from the East African Rift Valley to westernmost Africa. Chimp/bonobo map Bonobos have no national park, nothing to protect them from human hunting and encroachment except for the tropical diseases which limit human habitation in the area.

See the Pan Africa News article on human hunting of bonobos, entitled: "Economic Difficulties in Zaire and the Disappearing Taboo against Hunting Bonobos in the Wamba Area." An excerpt:

In 1991, a riot broke out in Kinshasa, the capital of Zaire, and research at Wamba was stopped for nearly 2 and a half years. Many bonobos appeared to have died or disappeared during this period. In April 1994 the members of E1 were censused and it was found that 10 bonobos including 2 young females disappeared during this break in research. I stayed at Wamba from February to July 1995 to do research, conduct conservation activity and to census the members of E1 and E2 groups. All E1 members checked in the previous year were still alive, but the number of bonobos in E2 had greatly decreased from what was observed five to six years ago. It can be concluded that most of the poaching was done during the absence of Japanese researchers.

 The Bonobo Protection Fund works to secure some protection for them, including hiring off-duty guards from a nearby national park. Contributions may be made to:

The Bonobo Protection Fund
Language Research Center
Georgia State University Foundation
University Plaza
Atlanta, Georgia 30303-3083 USA
1(404) 244 5825 (voice)
1(404) 244 5752 (fax)

From an earlier pre-downsizing Cincinnati Zoo web page:

Currently, bonobo populations number less than 20,000 individuals. This number is assumed to be dropping. Political unrest in Zaire is preventing researchers from entering the country, and has led to the end of negotiations with the government to set aside more protected land for bonobo habitat. Previous to the war in Zaire, reserves were being patrolled regularly in order to protect existing bonobo populations from poaching. Today, the guards have left their stations because of a lack of financial support and the threat of war. This leaves bonobos completely unprotected. Researchers fear the worst.

An excerpt from the The Bonobo Protection Fund literature:

Bonobos are also called pygmy chimpanzees. The name pygmy chimp was bestowed by Westerners in the 1930's, not because the animals were diminutive in size, but because they lived near human pygmies. It is important to understand that bonobos (Pan paniscus) are not chimpanzees (Pan troglodytes). While they share the same genus, bonobos and chimps are markedly distinct species.

The uncommon social structure, sexual behavior and intellectual capacity of bonobos reveal compelling clues about the roots of human nature. Bonobo anatomy is eerily similar to that of our early human ancestors. Bonobos and humans share 98% of the same genes.


[The appearance of bonobos make them] the most human-like of all apes. Their stride, their stance, their resting postures, their gestures, and their facial expressions all look more like our own than those of chimpanzees, gorillas or orangutans. Often, in the forest, large groups of 200 to 300 individuals come together for what appear to be "visits." During such times, there is almost constant "talking" or vocal exchange, as though they are catching up on past gossip---however, we really do not know, as study of these apes is barely in its infancy.


Zoo Exhibits of Bonobos

from deWaal and Lanting 1997 book BONOBO Europe: West Berlin (4 bonobos), Frankfurt (8), Cologne (5), Leipzig (3), Stuttgart (8), Wuppertal (5), Twycross (UK, 5), Planckendael (BE, 9), Apeldoorn (NL, multiple), and Antwerp (BE, 2).

Americas: Morelia (Mexico, 3 bonobos), San Diego Zoo (9) and Wild Animal Park (CA: 6), Cincinnati OH (6), Columbus OH (11), Fort Worth TX(3), Milwaukee WI(11).

Not accessible to the public are the 5 bonobos at the Yerkes Regional Primate Research Center and the 8 at the Language Research Center of Georgia State University. The total number of bonobos at zoos and research institutions is only 106, worldwide.

Columbus Zoo

has 11 bonobos (as of August 2000):

Adult males: 2 (Jimmy & Toby)
Adult females: 2 (Susie & Lady)
Juveniles: 1 male age 3-1/2 (Donny)
1 male age 2-1/2 (Ricky)
1 female age 1 yr (Tamia)
Mambo, a 9-year old male from the Morelia Zoo in Mexico. 
Lucy, an 11-year-old female from the Milwaukee Zoo.
Kimia, who is the daughter of Suzie and was born on June 13th, 1999, and 
Elekyia, the daughter of Lucy, born at the end of February, 2000.

Planckendael (outside Antwerp, Belgium)

A large, easily-viewed outdoor island, complete with wading opportunities for the bonobos. It is combined with an indoor space that is both interesting to the bonobos and easily seen by the visitor from either above or at floor level (access via the waterfall path). Nine bonobos. (Information from W. H. Calvin visit, 3 June 1995).

Travel Directions

By Car: Look for Exit 11 "Hofstade" on the fast highway between Brussels and Antwerp and take the road east. It ends in another highway within a few km; turn left (north), direction Mechelen. Watch for Planckendael signs when approaching a pedestrian crosswalk (Planckendael is an old estate on the left of the road; the parking is on the right). Note the storks nesting in the chimneys. The bonobos are in the new (1993) Africa Project.

By Train: To Mechelen, then bus "De Lijn" Route 285.

Planckendael is open every day of the year at 0900. The closing time varies with the season (1700 in winter, 1830 summer). The bonobos will be inside if the temperature is below 15°C.

Address and Phone
Planckendael, Leuvensesteenweg 582, B-2812 Muizen (near Mechelen), BELGIUM

Phone +(32)15/41.49.21 (weekends 41.43.49), fax 015/42.29.35

Planckendael is owned and operated by the Royal Zoological Society of Antwerp.

San Diego Zoo

If you haven't seen the bonobo exhibit at the main zoo (caution, it is impossible to find anything on their web site) in a few years, you have a treat in store, as they have constructed a magnificent exhibit (visit, October 1999).

The New York Times article of 22 April 1997, "Bonobo Society: Amicable, Amorous and Run by Females." Some quotes:

Even today there are only about 100 in zoos around the country, compared with the many thousands of chimpanzees in captivity. Bonobos are closely related to chimpanzees, but they have a more graceful and slender build, with smaller heads, slimmer necks, longer legs and less burly upper torsos. When standing or walking upright, bonobos have straighter backs than do the chimpanzees, and so assume a more humanlike posture. Far more dramatic than their physical differences are their behavioral distinctions. Bonobos are much less aggressive and hot-tempered than are chimpanzees, and are not nearly as prone to physical violence. They are less obsessed with power and status than are their chimpanzee cousins, and more consumed with Eros. As de Waal puts it in his book, "The chimpanzee resolves sexual issues with power; the bonobo resolves power issues with sex." Or more coyly, chimpanzees are from Mars, bonobos are from Venus.



Sue Savage-Rumbaugh and Roger Lewin, Kanzi (Wiley, 1994). See also the New York Times article and the book page at

The New York Times article (April 1998) on bonobo language abilities.

The New York Times article (February 1998) on bonobo symbolic communication in the wild.

E. Sue Savage-Rumbaugh, Stuart Shanker, Talbot J. Taylor, Apes, Language, and the Human Mind (Oxford University Press, May 1998).   

Frans de Waal, Frans Lanting, Bonobo: The Forgotten Ape (University of California Press 1997). As The Atlantic Monthly said:

What Professor de Waal describes is a society of mamma's boys, permanently subject to female control. It is also an erotic society, with sexual contacts conducted steadily, ingeniously, and with no discernible concern for sex or age. One of Mr. Lanting's many photographs sums up these apes rather well. It is of a male bonobo, standing straight as a palace sentry, well prepared for sexual action, and offering handfuls of sugarcane. Bonobo may lie at the root of civilized behavior.

deWaal's other books are also relevant to bonobos and chimpanzees (and see his website at the new Living Links Center):

Frans de Waal, Good Natured: The Origins of Right and Wrong (Harvard UP 1996).

        "If carnivory was indeed the catalyst for the evolution of sharing, it is hard to escape the conclusion that human morality is steeped in animal blood. When we give money to begging strangers, ship food to starving people, or vote for measures that benefit the poor, we follow impulses shaped since the time our ancestors began to cluster around meat possessors. At the center of the original circle, we find a prize hard to get but desired by many... this small, sympathetic circle grew steadily to encompass all of humanity — if not in practice then at least in principle.... Given the circle's proposed origin, it is profoundly ironic that its expansion should culminate in a plea for vegetarianism."

Frans de Waal, Peacemaking Among Primates (Harvard UP 1989).

Frans de Waal, Chimpanzee Politics: Sex and Power Among the Apes (Harper and Row 1982). I'm told there is a revised edition of this in the works from John Hopkins University Press, with a new set of photographs by de Waal.

Frans de Waal's excellent article on bonobo sex and society (Scientific American, March 1995) has the following suggestions for further reading:

Page maintained by
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at the University of Washington, Seattle. Revised 2004.

Web links to Bonobos


William H. Calvin, "Bonobos: The Left Bank Chimpanzees." Available at


Webbed Teaching Collection

This 'tree' is really a pyramidal neuron of cerebral cortex.  The axon exiting at bottom goes long distances, eventually splitting up into 10,000 small branchlets to make synapses with other brain cells.
William H. Calvin

University of Washington
Seattle WA 98195-1800 USA

It's an image (spam....)