Bonobo

Bonobo[1]
Conservation status
Endangered (IUCN 3.1)[2]
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Family: Hominidae Genus: Pan Species: P. paniscus
Binomial name
Pan paniscus Schwarz, 1929
Bonobo distribution

The Bonobo (IPA: /bə'noʊboʊ/^[3], Pan paniscus), which, until recently, usually was called the Pygmy Chimpanzee and less often, the Dwarf or Gracile Chimpanzee,^[4] is one of the two species making up the chimpanzee genus, Pan. The other species in genus Pan is Pan troglodytes, or the Common Chimpanzee. Although the name "chimpanzee" sometimes is used to refer to both species together, it is usually understood as referring to the Common Chimpanzee.

The Bonobo is endangered and only is found in the wild in the Democratic Republic of Congo. Along with the Common Chimpanzee, the Bonobo is the closest relative to humans. Since the two species are not proficient swimmers, it is possible that the formation of the Congo River 1.5–2 million years ago lead to the speciation of the Bonobo. They live south of the river, and thereby were separated from the ancestors of the Common Chimpanzee, which live north of the river.^[5]

German anatomist Ernst Schwarz is credited with having discovered the Bonobo in 1928, based on his analysis of a skull in the Tervuren museum in Belgium that previously had been thought to have belonged to a juvenile chimpanzee. Schwarz published his findings in 1929. In 1933, American anatomist Harold Coolidge offered a more detailed description of the Bonobo, and elevated it to species status.

The species is distinguished by relatively long legs, parted hair on their head, a matriarchal culture, and the prominent role of sexual activity in its society.

This primate is mainly frugivorous, but supplements its diet with leaves and sometimes the meat of small vertebrates, such as flying squirrels and infant duikers,^[6] and invertebrates.^[7]

Name

Common name

The name Bonobo first appeared in 1954, when Edward Tratz and Heinz Heck proposed it as a new and separate generic term for pygmy chimpanzees. The term has been reported variously as being a word for "chimpanzee" or "ancestor" in a Bantu language. Another suggestion for the derivation of the name is that the name is a misspelling of the name of the town of Bolobo on the Congo River, which has been associated with the collection of chimps in the 1920s.^[8]

Taxonomy

The scientific name for the Bonobo is Pan paniscus. Initial genetic studies have characterised their DNA as more than 98% identical to that of Homo sapiens.^[9] More recent studies have shown that chimpanzees are more closely related to humans than to the gorillas.^[10] The most recent genetic analyses of chimpanzee and human genetic similarity come from whole genome comparisons and have shown that the differences between the two species are more complex, both in extent and character, than the historical 98% figure suggests.

In the seminal Nature paper reporting on initial genome comparisons, researchers identified thirty-five million single-nucleotide changes, five million insertion or deletion events, and a number of chromosomal rearrangements which constituted the genetic differences between chimpanzees and humans, covering ~5% of both genomes.^[11] While many of these analyses have been performed on the Common Chimpanzee rather than the Bonobo, the differences between the two chimpanzee species are unlikely to be substantial enough to affect the Pan-Homo comparative data significantly.

There still is controversy, however. Scientists such as Morris Goodman ^[12] of Wayne State University in Detroit argue that the Bonobo and Common Chimpanzee are so closely related to humans, that their genus name also should be classified with the human genus Homo: Homo paniscus, Homo sylvestris, or Homo arboreus. An alternative philosophy suggests that the term Homo sapiens is the misnomer rather, and that humans should be reclassified as Pan sapiens. In either case, a name change of the genus would be problematic because it would complicate the taxonomy of other species closely related to humans, including Australopithecus.

Recent DNA evidence suggests the Bonobo and Common Chimpanzee species effectively separated from each other less than one million years ago.^[13][14] The chimpanzee line split from the last common ancestor shared with humans approximately four to six million years ago. Because no species other than Homo sapiens has survived from the human line of that branching, both Pan species are the closest living relatives of humans—and cladistically—are equally close to humans.

Physical characteristics

Bonobo

The Bonobo is more gracile (slight in form) than the Common Chimpanzee and females are somewhat smaller than males. Its head is smaller than that of the Common Chimpanzee with less prominent brow ridges above the eyes. It has a black face with pink lips, small ears, wide nostrils, and long hair on its head that forms a part. Females have slightly more prominent breasts, in contrast to the flat breasts of other female apes, although not so prominent as those of humans. The Bonobo also has a slim upper body, narrow shoulders, thin neck, and long legs when compared to the Common Chimpanzee. The Bonobo walks upright approximately 25% of the time during ground locomotion. Its quadrupedal ground locomotion generally is characterized by forelimb 'palm walking', similar to orangutans and in contrast to the predominant use of knuckles as characteristic of gorillas and the Common Chimpanzees. These physical characteristics and its posture, give the Bonobo an appearance more closely resembling humans than that of the Common Chimpanzee (see: bipedal Bonobos). The Bonobo also has highly-individuated facial features, as humans do, so that one individual may look significantly different from another, a characteristic adapted for visual facial recognition in social interaction.

Psychological characteristics

Frans de Waal, one of the world's leading primatologists, states that the Bonobo often is capable of altruism, compassion, empathy, kindness, patience, and sensitivity.

Recent observations in the wild indicate that the males among the related Common Chimpanzee communities are extraordinarily hostile to males from outside of the community. Parties of males 'patrol' for the unfortunate neighbouring males who might be traveling alone, and attack those single males, often killing them. (Some researchers have suggested, however, that this behaviour has been caused by a combination of human contact and interference and massive environmental stress caused by deforestation and a corresponding range reduction.^[15]) This does not appear to be the behavior of the Bonobo males or females, both of whom seem to prefer sexual contact over violent confrontation with outsiders. The Bonobo live in different areas from the more aggressive Common Chimpanzee. Neither of the species swims, and they sometimes inhabit ranges on opposite sides of the great Congo River. It has been hypothesized that Bonobos are able to live a more peaceful lifestyle in part, because of an abundance of nutritious vegetation in their natural habitat, allowing them to travel and forage in large parties.

The popular image of the Bonobo as a "peaceful ape" has come under fire by observations of artificially-confined populations. Accounts exist of Bonobos confined in zoos mutilating one another and engaging in bullying. These incidents may be due to the practice in zoos of separating mothers and sons, which is contrary to their social organization in the wild. Bonobo society is dominated by females, and severing the lifelong alliance between mothers and their male offspring may make them vulnerable to female aggression. De Waal has warned of the danger of romanticizing Bonobos: "All animals are competitive by nature and cooperative only under specific circumstances" as well as writing that "When first writing about their behavior, I spoke of 'sex for peace' precisely because bonobos had plenty of conflicts. There would obviously be no need for peacemaking if they lived in perfect harmony". In marked contrast to the Common Chimpanzee there are no confirmed reports of lethal aggression between Bonobos, either in the wild or in captivity. The immature state of Bonobo research in the wild, compared to that of the Common Chimpanzee, however, means that lethal aggression between Bonobos could be discovered.

Hohmann and Surbeck published in 2008 that Bonobos sometimes do hunt monkey species. Having observed a group of bonobos in Salonga National Park for five years they witnessed five incidents where Bonobos preyed on groups of monkeys. Their research indicates it was deliberate hunting, where a group of Bonobos would coordinate their actions—contrary to their normal hunting behaviour, which is quite solitary and less purposeful. In three occasions the hunt was successful and infant monkeys were captured, once a redtail monkey and twice a Cercopithecus wolfi. The spoils, however, were distributed quite peacefully among the members of the group.^[16][17]

Social behavior

Females are considered to have a higher social status in their matriarchal culture. Strong female bonding allows groups of female Bonobos to dominate the community. Aggressive encounters between males and females are rare, and males are tolerant of infants and juveniles. A male's status is derived from the status of his mother. The mother-son bond often stays strong and continues throughout life. While social hierarchies do exist, rank does not play so prominent a role as it does in other primate societies.

Bonobo fishing for termites

Bonobo party size tends to be variable since the groups exhibit a fission-fusion pattern. A tribe of approximately one hundred will split into small groups during the day while looking for food, and then come back together to sleep. They sleep in trees on nests they construct. Unlike Common Chimpanzees, who are known to hunt monkeys, Bonobos primarily are frugivores, although they do eat insects and occasionally have been observed catching small mammals such as squirrels and duikers.

Sexual social behavior

Sexual intercourse plays a major role in Bonobo society, being used as a greeting, a means of conflict resolution, and post-conflict reconciliation. With the exception of a pair of Congoese gorillas observed doing so,^[18] Bonobos were thought to be the only non-human apes to have been observed engaging in all of the following sexual activities: face-to-face genital sex, tongue kissing, and oral sex.^[19] In scientific literature, the female-female sexual behavior often is referred to as GG rubbing or genital-genital rubbing.

Sexual activity happens within the immediate family as well as outside it, and often involves adults and children, including infants.^[20] Bonobos do not form permanent relationships with individual partners. They also do not seem to discriminate in their sexual behavior by gender or age, with the possible exception of abstaining from sexual intercourse between mothers and their adult sons; some observers believe these pairings are taboo. When Bonobos come upon a new food source or feeding ground, the increased excitement will usually lead to communal sexual activity, presumably decreasing tension and allowing for peaceful feeding.^[21]

Bonobo males frequently engage in various forms of male-male genital sexual behavior, (frot).^[22][23] In one form, two males hang from a tree limb face-to-face while "penis fencing"^[24][25]. Frot also may occur when two males rub their penises together while in face to face position. A special form of frot called "rump rubbing" occurs to express reconciliation between two males after a conflict, when they stand back-to-back and rub their scrotal sacs together.

Bonobo females also engage in female-female genital sexual behavior, (tribadism), to bond socially with each other, thus forming a female nucleus of Bonobo society. The bonding among females allows them to dominate Bonobo society - although male Bonobos are individually stronger, they cannot stand alone against a united group of females.^[25] Adolescent females often leave their native community to join another community. Sexual bonding with other females establishes the new females as members of the group. This migration mixes the Bonobo gene pools, providing genetic diversity.

Bonobo reproductive rates are not any higher than that of the Common Chimpanzee. Female Bonobos carry and nurse their young for five years and can give birth every five to six years. Compared to Common Chimpanzees, Bonobo females resume the genital swelling cycle much sooner after giving birth, allowing them to rejoin the sexual activities of their society. Also, Bonobo females who are sterile or too young to reproduce still engage in sexual activity.

Craig Stanford, an American primatologist, has challenged the claim that Bonobos are more sexually active than Common Chimpanzees. Stanford compared existing data on Common Chimpanzees and Bonobos in the natural habitat and found that female Common Chimpanzees copulated at least as often as female Bonobos, while he recorded that male chimpanzees copulated more than male Bonobos.^[26] His comparison excluded same-sex sexual contacts, however, which are very common in Bonobos. De Waal's book on Bonobos includes interviews with field workers and relies on the studies by Takayoshi Kano, the only scientist to have worked for two decades with wild Bonobos.^[27] New studies in Africa by Gottfried Hohmann, a research associate at the Max Planck Institute for Evolutionary Anthropology of Leipzig, Germany, relate significant violence, but fact remains that there are thus far no documented cases of lethal aggression among Bonobos, in sharp contrast to the evidence for Common Chimpanzees.^[28]

Closeness to humans

Bonobos are capable of passing the mirror-recognition test for self-awareness. They communicate primarily through vocal means, although the meanings of their vocalizations are not currently known. However, most humans do understand their facial expressions^[9] and some of their natural hand gestures, such as their invitation to play. Two Bonobos at the Great Ape Trust, Kanzi and Panbanisha, have been taught how to communicate using a keyboard labeled with lexigrams (geometric symbols) and they can respond to spoken sentences. Kanzi's vocabulary consists of more than 500 English words^[29] and he has comprehension of around 3,000 spoken English words.^[30] Some, such as philosopher and bioethicist Peter Singer, argue that these results qualify them for the "rights to survival and life," rights that humans theoretically accord to all persons.

There are instances in which non-human primates have been reported to have expressed joy. One study analyzed and recorded sounds made by human babies and Bonobos when they were tickled.^[31] It found although the Bonobo's laugh was a higher frequency, the laugh followed a similar spectrographic pattern to human babies.^[31]

Habitat

Around 10,000 Bonobos are found only south of the Congo River and north of the Kasai River (a tributary of the Congo),^[20] in the humid forests of the Democratic Republic of Congo of central Africa. They are an endangered species, due both to habitat loss and hunting for bushmeat, the latter activity having increased dramatically during the current civil war due to the presence of heavily armed militias even in remote "protected" areas such as Salonga National Park. Today, at most several thousand Bonobos remain. This is part of a more general trend of ape extinction.

Conservation efforts

Since 1996, the first and second Congo wars in the Democratic Republic of Congo (DRC) have had a major impact on both the Bonobo and human population. The people of the DRC now, more than ever, have a desire to protect their interests. Bonobos are in danger of being hunted to extinction. The key to Bonobo conservation efforts is balancing these issues.

As the Bonobo's habitat is shared with people, the ultimate success of conservation efforts will rely on local and community involvement. The issue of parks vs. people,^[32] is very cogent in the Cuvette Centrale, the Bonobo's range. There is strong local and broad-based Congolese resistance to establishing national parks, as indigenous communities often have been driven from their forest homes by the establishment of parks. In Salonga National Park, the only national park in the Bonobo habitat, there is no local involvement, and recent surveys indicate that the Bonobo, the African Forest Elephant, and other species have been severely devastated by poachers and the thriving bushmeat trade. In contrast to this, there are areas where the Bonobo and biodiversity still thrive without any established parks, due to the indigenous beliefs and taboos against killing Bonobos.

In 1995, concern over declining numbers of Bonobos in the wild led the Zoological Society of Milwaukee in Milwaukee, Wisconsin, with contributions from Bonobo scientists around the world, to publish the Action Plan for Pan paniscus: A Report on Free Ranging Populations and Proposals for their Preservation. The Action Plan compiles population data on Bonobos from twenty years of research conducted at various sites throughout the Bonobo's range. The plan identifies priority actions for Bonobo conservation and serves as a reference for developing conservation programs for researchers, government officials, and donor agencies.

Acting on Action Plan recommendations, the ZSM developed the Bonobo and Congo Biodiversity Initiative (BCBI). This program includes habitat and rain-forest preservation, training for Congolese nationals and conservation institutions, wildlife population assessment and monitoring, and education. The Zoological Society has conducted regional surveys within the range of the Bonobo in conjunction with training Congolese researchers in survey methodology and biodiversity monitoring. The Zoological Society’s initial goal was to survey Salonga National Park to determine the conservation status of the Bonobo within the park and to provide financial and technical assistance to strengthen park protection. As the project has developed, the Zoological Society has become more involved in helping the Congolese living in Bonobo habitat. The Zoological Society has built schools, hired teachers, provided some medicines, and, as of 2007^[update], started an agriculture project to help the Congolese learn to grow crops and depend less on hunting wild animals.

During the wars in the 1990s, researchers and international non-governmental organizations (NGOs) were driven out of the Bonobo habitat. In 2002, the Bonobo Conservation Initiative initiated the Bonobo Peace Forest Project in cooperation with national institutions, local NGOs, and local communities. The Peace Forest Project works with local communities to establish a linked constellation of community-based reserves, managed by local and indigenous people. Although there has been only limited support from international organizations, this model, implemented mainly through DRC organizations and local communities, has helped bring about agreements to protect over 5,000 square miles (13,000 km²) of the Bonobo habitat. According to Dr. Amy Parish, the Bonobo Peace Forest "…is going to be a model for conservation in the 21st century."^[33]

This initiative has been gaining momentum and greater international recognition and it recently has gained greater support through Conservation International, the Global Conservation Fund, United States Fish and Wildlife Service's Great Ape Conservation Fund, and the United Nations' Great Apes Survival Project.

With grants from the United Nations, USAID, the U.S. Embassy, the World Wildlife Fund, and many other groups and individuals, the Zoological Society also has been working to:

• survey the Bonobo population and its habitat in order to find ways to help protect these apes
• develop anti-poaching measures to help save apes, forest elephants, and other endangered animals in Congo's Salonga National Park, a U.N. World Heritage Site
• Provide training, literacy education, agricultural techniques, schools, equipment, and jobs for Congolese living near Bonobo habitats so that they will have a vested interest in protecting the great apes. As of 2007^[update], the ZSM started an agriculture project to help the Congolese learn to grow crops and depend less on hunting wild animals.
• model small-scale conservation methods that can be used throughout Congo

Starting in 2003, the U.S. government allocated $54 million to the Congo Basin Forest Partnership. This significant investment has triggered the involvement of international NGOs to establish bases in the region and work to develop Bonobo conservation programs. This initiative should improve the likelihood of Bonobo survival, but its success still may depend upon building greater involvement and capability in local and indigenous communities.^[34]

The Congo is setting aside more than 11,000 square miles (28,000 km²) of rain forest to help protect the endangered Bonobo, in this Central African country. U.S. agencies, conservation groups, and the Congolese government have come together to set aside 11,803 square miles (30,570 km²) of tropical rain forest, the U.S.-based Bonobo Conservation Initiative. The area amounts to just over 1 percent of the vast Congo - but that means a park larger than the state of Massachusetts.

The Bonobo population is believed to have declined sharply in the last thirty years, though surveys have been hard to carry out in war-ravaged central Congo. Estimates range from 60,000 to fewer than 5,000 living, according to the World Wildlife Fund.

The Sankuru reserve also contains Okapi, closely related to the Giraffe, that also is native to Congo, elephants, and at least ten other primate species.

In addition, concerned parties have addressed the crisis on several science and ecological websites. Organizations such as the World Wide Fund for Nature, the African Wildlife Foundation, and others are trying to focus attention on the extreme risk to the species. Some have suggested that a reserve be established in a more stable part of Africa, or on an island in a place such as Indonesia. Awareness is ever increasing and even non scientific or ecological sites have created various groups to collect donations to help with the conservation of this species.

See also

• Chimpanzee genome project
• Great ape personhood
• Polygynandry
• List of apes – notable individual apes
• List of fictional apes

References

Further reading

Books

• de Waal, Frans and Frans Lanting, Bonobo: The Forgotten Ape, University of California Press, 1997. ISBN 0-520-20535-9; ISBN 0-520-21651-2 (trade paperback)
• de Waal, Frans, Our Inner Ape, Riverhead Books, 2005. ISBN 1-57322-312-3
• Kano, Takayoshi, The Last Ape: Pygmy Chimpanzee Behavior and Ecology, Stanford, CA: Stanford University Press, 1992.
• Savage-Rumbaugh, Sue and Roger Lewin, Kanzi: The Ape at the Brink of the Human Mind, John Wiley, 1994. ISBN 0-471-58591-2; ISBN 0-471-15959-X (trade paperback)

Articles

• de Waal, Frans, "Bonobos, Left & Right", Skeptic, August 8, 2007.
• DeBartolo, Anthony. "The Bonobo: 'Newest' apes are teaching us about ourselves", Chicago Tribune June 11, 1998.
• Parker, Ian. "Swingers: Bonobos are celebrated as peace-loving, matriarchal, and sexually liberated. Are they?" The New Yorker, July 30, 2007.

External links

• ARKive - BBC images and movies of the bonobo (Pan paniscus)
• Evolution: Why Sex?
• Bonobo Social Organization
• Bonobos: Wildlife summary from the African Wildlife Foundation
• Chimpanzee and Human Behaviors
• Bonobos by D'Lynn Waldron
• Bonobos: The Left-Bank Chimpanzees
• The Bonobo Initiative
• Bonobo Sex and Society
• The Great Ape Trust: Studying the Bonobo
• NPR's Science Friday piece on bonobos
• Primate Info Net Pan paniscus Factsheet
• U.S. Fish & Wildlife Service Species Profile
• "The Last Great Ape", an episode of Nova.
• Susan Savage-Rumbaugh: Apes that write, start fires and play Pac-Man (TED Talk)
• Image: bonobos genito-genital rubbing
• Lola ya Bonobo Sanctuary

Ape-related articles Ape study Ape language · Ape Trust · Dian Fossey · Birutė Galdikas · Jane Goodall · Chimpanzee genome project · Human genome project Legal status Personhood · Research ban · Declaration · Kinshasa Declaration · Great Ape Project · Survival Project See also Bushmeat · Ape extinction · List of notable apes · List of fictional apes · Human evolution · Mythic humanoids · Hominid · Planet of the Apes