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Bonobo
The bonobo (Pan paniscus) is a great ape that is very closely related to
the chimpanzee. It is the least known of the great apes because it lives in a remote
rain-forest region of central Africa, and it was only identified as a species in
1933. Although often referred to as the pygmy chimpanzee, pygmy is a misnomer because
the body weight of the bonobo is, on average, the same or slightly less than that
of the eastern common chimpanzee (Pan troglodytes schweinfurthi). Compared
to the common chimpanzee, the body weight of the bonobo is proportioned differently;
the center of gravity is lower, making it possible for the bonobo to stand more
erect and walk bipedally (on two feet). Bonobos have longer limbs (relative to trunk
length) and their build is generally more slender and graceful than chimpanzees.
The lanky body structure of the bonobo is thought to be an adaptation for climbing
and living an arboreal (living in the trees) lifestyle in the rain forest. The head
and ears of bonobos are noticeably smaller, and there is less brow mass over the
eyes than is characteristic of chimpanzees. The facial skin is darkly pigmented,
and the hair is black, usually parted in the middle of the head with bushy sideburns
on b
oth sides of the face. The bonobo’s vocalizations are high-pitched squeals.
Because of the similar morphological traits (physical appearance) between bonobos
and humans, some anthropologists consider the bonobo to be the best living prototype
for the common ancestor of humans. While this controversy is unresolved, it has
been established through molecular genetic analysis that the chimpanzee genus, Pan,
is the most closely related to humans and shares approximately 98% genetic identity.
It follows that bonobos and chimpanzees share many human-like morphological, physiological
and behavioral traits.
Bonobo Facts
Range
Bonobos are confined geographically to a small region in the Democratic Republic of Congo, in the Congo River Basin, south of the Congo River.
Habitat
Unlike the common chimpanzee, which lives in a variety of habitats, the bonobo is found primarily in lowland rain forests. Its has a more arboreal lifestyle than other African apes.
Diet
Bonobos primarily feed on arboreal fruits, leaves, and pith from stems. They are
also known to occasionally eat insects and hunt small mammals. Bonobos also have
been observed to slap water up from a stream and eat both invertebrates and fish.
Social Organization
Certain aspects of bonobo social organization differ from the chimpanzee and other great apes. Bonobos are most frequently found in mixed age and sex groups with adults, juveniles and infants of both sexes freely associating with each other. There is a less pronounced dominance hierarchy in the bonobo’s social structure. Unique among great apes, bonobos display a greater prevalence of strong female-female bonding as opposed to the predominance of male-male bonding observed in common chimpanzees. One special feature observed in bonobo society is the low level of aggression between individual bonobos. Bonobos are less apt to engage in physical conflicts and confrontations with other groups of bonobos. Their generally peaceful society is attributed to the evolution of a highly complex social system. Bonobos have developed a set of ritualized socio-sexual behaviors that are specific to their species. Sexual behaviors, displayed by individuals of all ages, have evolved to strengthen group cohesion. For example, mating is common between male and female adults even when the female is not fertile. There is also a higher frequency of homosexual behavior among bonobos of all ages (especially among adult females), and genital contact functions as social appeasement during times of group tension. Bonobos mature at about 7 to 10 years old in captivity, and at about 12 to 14 years old in the wild. Captive females give birth to one infant approximately every five years, and gestation lasts around eight months. While the infant is primarily dependent on its mother for the first four years of life, its father and siblings are also strongly associated family members.
Conservation Status
The Red Data Book, published by the International Union for the Conservation of
Nature and Natural Resources, lists the bonobo as endangered due to exploitation
by humans and loss of habitat. There are no valid estimates of the number of bonobos
remaining in the wild. What is known is that bonobos no longer occur in much of
their historical rang
e. Wild populations have been reduced greatly by deforestation
and human encroachment, and bonobo populations are discontinuous and widely scattered.
Threats to Survival
Even historically the bonobo has been considered to be a rare species relative to other apes because of its habitat limitations and small range. The bonobo is threatened by rain-forest destruction and is hunted for food and sale to the pet trade. Most recent reports from field researchers indicate increased poaching of bonobos for food. The increase in poaching of bonobos, and of all wildlife in the region, for food is attributed to nationwide food shortages and an influx of weapons and refugees from regional conflicts. One of the major threats to bonobos is that their range lies entirely within the country of the Democratic Republic of Congo. Thus the species is extremely vulnerable to political and social conflicts that may arise in Congo; the recent civil war has had an inestimable impact on Congo’s wild bonobo population.
Zoo Programs
All institutions housing bonobos in North America are members of the Bonobo SSP.
Bonobos are not commonly found in zoos; as of November 2001, 71 bonobos live in
eight zoological institutions in the U.S. and Mexico. In contrast, there are about
350 chimpanzees, 300 western lowland gorillas, and 250 orangutans in U.S. zoos.
Because of the small size of the captive bonobo population, intensive management
is required to preserve genetic diversity, and achieve demographic stability to
ensure a self-sustaining captive population. Furthermore, these management strategies
must be conducted on a worldwide basis in order to attain the minimum viable population
size required for long-term survival. Toward this end, the Bonobo SSP works in collaboration
with our European counterpart, the Bonobo European Endangered Species Programme (EEP).
Currently, the Bonobo SSP and EEP are developing a joint plan, Bonobo (Pan paniscus)
Master Plan 2001: Recommendations for the Global Captive Population. The Master
Plan provides breeding and management recommendations for all individual bonobos.
Together, the two
management groups also published a husbandry manual entitled The
Care and Management of Bonobos in Captive Environments. By routinely updating the
husbandry manual and supporting behavioral research, the Bonobo SSP and EEP address
problems concerning social and reproductive behavior, social development, environmental
health, and husbandry standards. Breeding recommendations take into account the
social needs of individuals in an effort to preserve normal behavior of the species
in captivity.
Conservation Information
In the Congo, there are currently only two protected areas for the bonobo: the Salonga National Park and the Luo River Scientific Reserve near Wamba. The Salonga National Park is the only federally protected reserve for bonobos, but their status in the park is unknown. The Luo River Reserve is a scientific research area that receives local government protection. At present, protection of bonobos within these reserves is highly dependent on the existence of expatriate research programs in these areas.
The current state of our knowledge concerning bonobo conservation is summarized in the Action Plan for Pan paniscus: Report on Free Ranging Populations and Recommendations for Their Preservation. The Action Plan was published by the Zoological Society of Milwaukee in 1995 and is endorsed by the IUCN Species Survival Commission. The Action Plan identifies priorities for bonobo conservation and serves as a guide for researchers, government officials and donor agencies in developing conservation programs. The Action Plan discusses the need for: regional surveys to determine where bonobo populations exist; conservation education throughout the Congo; economic benefits for local people from conservation projects; enforcement of anti-poaching laws; and enforced habitat protection.
As noted in the Action Plan, one of the major obstacles to developing conservation strategies for the bonobo is the lack of knowledge about where bonobo populations occur and the extent to which these are threatened. The Action Plan, therefore, recommends regional surveys. The Bonobo SSP will support one such survey in the Salonga National Park. If a viable population of bonobos is confirmed, the Salonga Park represents the largest potential area of protection for bonobos. As part of this project, Congolese field biologists will receive training in survey methodology in order to conduct the Salonga survey and other needed bonobo surveys.
Contacts
SSP Coordinator: Gay Reinartz,
Ph.D. Conservation Coordinator
Zoological Society of Milwaukee
1421 N. Water Street
Milwaukee, WI 53202
(414) 276-0339
gayr@zoosociety.org
Bonobo Conservation Issues
AZA Bonobo SSP Status
The Bonobo Species Survival Plan (SSP) contributes to bonobo conservation through research, public education, and field projects. All institutions housing bonobos in North America are members of the Bonobo SSP. The SSP works in collaboration with the Bonobo European Endangered Species Programme (EEP). Currently, the SSP and EEP are developing a joint plan that provides breeding and management recommendations for zoos. Together, the two management groups also published a husbandry manual entitled The Care and Management of Bonobos in Captive Environments. To learn more, visit the Bonobo SSP website at: www.zoosociety.org/Conservation/Bonobo/SSP.php.
© 2009 Ape TAG®