CONTENTS

Living OrganismsAnimalia / Craniata / Mammalia / Primates / Hominidae / Pan / Species

Pan paniscus - Bonobo (Click photographs/illustrations for full picture & further details)

Bonobo - Pan paniscus Bonobo - Pan paniscus Infant bonobo - Pan paniscus Bonobo mother resting while her infant plays nearby Bonobo Bonobo pearching on top of pole Bonobo perching on top of climbing structure Bonobo climbing Bonobos using climbing opportunitie. Click here for full page view with caption Pan paniscus - Bonobo. Click here for full page view with caption Pan paniscus - Bonobo. Click here for full page view with caption Male bonobo calling. Click here for full page view with caption Bonobo wading chest-deep. Click here for full page view with caption Orphaned bonobos need close physical contact. Click here for full page view with caption Female bonobos GG rubbing. Click here for full page view with caption Click here for full-page view with caption Click here for full-page view with caption First tooth appearing in an infant bonobo. Click here for full page view with caption Infant bonobo holding rope. Click here for full-page view with caption Infant bonobo climbing. Click here for full-page view with caption VIDEO:

INDEX - INFORMATION AVAILABLE

GENERAL & REFERENCES

APPEARANCE / MORPHOLOGY

LIFE STAGES / NATURAL DIET / PHYSIOLOGY

BEHAVIOUR

HABITAT & RANGE

CONSERVATION

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General and References

Alternative Names (Synonyms)

  • Dwarf chimpanzee (W2.Sept09.w1)
  • Gracile chimpanzee (B580.5.w5)
  • Pygmy chimpanzee (B580.5.w5)
  • Chimpanzé nain (B580.5.w5)
  • Chimpanzé Nain (French)  (W2.Sept09.w1)
  • Chimpanzé noir (B580.5.w5)
  • Chimpancé pigmeo (Spanish) (W2.Sept09.w1)
  • Chimpanzé pygmée (French) (W2.Sept09.w1)
  • Ejá (Limongo) (B586.17.w17)
  • Eliya (Lontomba, Bikoro area) (B586.17.w17)
  • Elia, plural Bilia (N40.10.w6)
  • Mokumbusu, Sokomunyo (Lingala, Swaili) (B586.17.w17)

Names for new-borns / juveniles

  • Infant
  • Juvenile

Names for males

  • Male

Names for females

  • Female

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General Appearance

Adult: Overall black, with black face. Arms and legs similar in length. No tail, but a tail tuft of fur. The hair on the head is long with a distinctive central parting. (B580.3.w3, B580.5.w5)
  • Bonobos have predominantly black body hair, with the head not going bald later in life; the tail tuft persists in adults; the face and hands are dark even in infants (pale in Pan troglodytes - Chimpanzees). The ears are relatively small, while the forehead is high and round; the supraorbital torus (eyebrow ridge) is smaller than in Pan troglodytes. There is webbing between the digits,  of the second and third toes. (B577.1.w1)

Newborn: Overall black, with black face. (B580.3.w3)

Similar Species

 

Bonobos are very similar to Pan troglodytes - Chimpanzees and were originally described as a subspecies of the chimpanzee. It is thought that the two species diverged somewhere between 1.3 and 3.0 million years ago. Differences include: (B580.3.w3)
Bonobo Chimpanzee
Face at birth black Face at birth pink
Lips red Lips brown or black
Almost no beard White beard in adults
Prominent side-whiskers from birth No side-whiskers
Prominent white tail tuft of fur retained as adults White tail tuft of fur in juveniles only
Skull short and very rounded Skull longer, forehead lower, brow ridges more prominent
Eyes set further apart and less deep Eyes set closer together, more deepset
Clitoris large and shifted ventrally Clitoris not enlarged, not shifted ventrally.
  • Skin on the face and extremities dark (pale flesh colour around the eyes and lips) throughout life, versus pale flesh colour in infant chimpanzees, and often freckled or mottled in adults. (B577.1.w1)
  • Long hair on the cheeks in bonobos, not in chimpanzees. (B577.1.w1)
  • Body hair black (very rarely brown); in chimpanzees, the body hair tends to start black but turn lighter brown or grey in adults. (B577.1.w1)
  • Ears are relatively small and set close to the head; in chimpanzees they are larger and jut out more. (B577.1.w1)
  • The hair is dense on the head, even in older adults, while some adult chimps develop a bald forehead. (B577.1.w1)
  • At the base of the spinal column there is a bald spot and below this an inconspicuous white tail tuft, in adults as well as juveniles; in chimpanzees the white tail tuft is conspicuous in infants but disappears in adults. (B577.1.w1)
  • In about 50% of individuals there is webbing on the feet, between the second and third toes; interdigital webbing is rare in chimpanzees. (B577.1.w1)
  • Bonobos have a relatively small, slender body with relatively long limbs and forelimbs and hindlimbs about equal in length so the body is horizontal when the individual is in a quadripedal stance; chimpanzees have a relatively larger, heavier body and relatively shorter limbs, with longer forelimbs than hindlimbs, so that the body is higher at the front than at the back when the individual stands quadripedally. (B577.1.w1)
    • The forelimb bones are (insignificantly) shorter in Pan paniscus than in Pan troglodytes, but the hindlimb bones are significantly longer. (B577.1.w1)
  • Bonobos have a relatively high and rounded forehead with a small brow ridge; in chimpanzees the forehead is relatively lower and the brow ridge more massive. (B577.1.w1)
  • Compared to Pan troglodytes, the chest girth is smaller and the legs longer. (J576.23.w1)

Sexual Dimorphism

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References

Species Authors & Referees

Editor: Dr Debra Bourne MA VetMB PhD MRCVS (V.w5)

ORGANISATIONS

ELECTRONIC LIBRARY
(Further Reading)
Click image for full contents list of ELECTRONIC LIBRARY

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Husbandry Information

Notes

  • Bonobos are large, strong primates, very good at climbing and possessing opposable thumbs.
  • They are highly intelligent and have a strong social structure involving multi-male, multi-female groups.
  • The behavioural, social and psychological requirements of bonobos must be taken into consideration in enclosure design and husbandry.

Management Techniques

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Appearance / Morphology

Measurement & Weight

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.

LENGTH
Adult: 
Head and body length 700 - 828 mm
Newborns: --

HEIGHT
Adults and sub-adults: Mean 1.153 m.
Juveniles: --

WEIGHT
Adult: 
Average about 45 kg for males, 33 kg for females.
Newborns: About 1.18-1.76 kg, based on captive infants at 1-4 days of age.

GROWTH RATE

  • Infant bonobos grow more slowly than do Pan troglodytes - Chimpanzees. Hand-reared infants have gained weight faster than mother-reared infants. It is estimated that in the wild, infants reach about 3 kg by three years old - only about 2.3 times their birth weight. In contrast, bottle-reared infants may reach 3 kg by six months of age. 

(References are available in detailed literature reports below)

CLICK THE LINKS FOR Literature Reports

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Head and Neck

EDITORIAL SUMMARY

First tooth appearing in an infant bonobo. Click here for full page view with caption

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.

GENERAL HEAD STRUCTURE:
Adult:
Bonobos have a relatively high and rounded forehead with a small brow ridge, relatively small, rounded, hairless ears, and long hair on the sides of the head. The skull is longer than it is broad, but the skull is more rounded and globular than in Pan troglodytes; cranial capacity is slightly lower.
Newborn: --

DENTITION:
Adult:
Dental formula i 2/2, c 1/1, pm 2/2, m 3/3 (x 2, total 32 teeth). There is no sexual dimorphism in tooth size except for slightly longer, broader canine teeth in males. 
Newborn:
The deciduous dental formula is i2/2, c 1/1, dm 2/2. 

EYES:
Adult:
Bonobos have brown eyes.
Newborn:
--

(References are available in detailed literature reports below)

CLICK THE LINKS FOR Literature Reports

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Legs, Spine and Tracks

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.
  • Bonobos have similar leg length to Pan troglodytes - Chimpanzee but a shorter body so the legs appear longer relative to the body. They also have shorter arms than Pan troglodytes. In bonobos, the hind limbs make up 24.2% of the total body weight while the upper limbs weigh 15.8% of the total. Both the thumbs and the big toes are opposable; the fingers are long relative to the thumb, making a precision grip difficult.

(References are available in detailed literature reports below)

CLICK THE LINKS FOR Literature Reports

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Tail

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.
  • As with all the apes, bonobos do not have a tail.

(References are available in detailed literature reports below)

CLICK THE LINKS FOR Literature Reports

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Skin / Coat / Pelage

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.

Adult: As with all the great apes, the pelage is short, shaggy and coarse. The hair of bonobos is basically black as is the skin of the face, while the skin on the body is white. The face is practically hairless and the ears are hairless, although there is long hair on the sides of the face. There is a white tail tuft.

Adult Colour variations: Occasional individuals are brown rather than black.

Newborn/Juvenile: Newborn bonobos have a black face (not pink as in Pan troglodytes). The skin of the rump is bare and pink, with the white "tail tuft" only developing later.

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Appearance- Morphology- Skin-Coat-Pelage (Literature Reports)

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Detailed Anatomy Notes
(Summary information provided for pertinent species-specific data cross-referenced in Wildpro)

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.
  • There are usually 17 thoracolumbar vertebrae, but there are some variations.
  • Bonobos have a relatively large brain, about 411 cubic cm.

Further information is available within this section on the structure of the skeleton, and the reproductive, gastrointestinal, cardiovascular and respiratory systems.

(References are available in detailed literature reports below)

CLICK THE LINKS FOR Literature Reports
Bonobo Pan paniscus - Detailed Anatomy Notes (Literature Reports)

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Life Stages / Natural Diet / Physiology

Life Stages

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.

BREEDING SEASON: There is no particular breeding season in bonobos.

OESTRUS/OVULATION: The oestrous cycle lasts 21-55 days. Hormone measurements have shown that the luteal phase lasts 11-15 days but the follicular phase is more variable in length, 17-40 days. Swelling of the sexual skin may be noted for about two thirds of the whole cycle, with maximum swelling for about half this time and ovulation taking place towards the end of the fully swollen period.

GESTATION/PREGNANCY: Gestation lasts for about 220-240 days (about 7.3 - 8 months).

PARTURITION/BIRTH: Data from zoos indicates that labour lasts 2-10 hours, averaging about 7 hours; most births have occurred at night, unobserved. It is generally considered that there is no particular birth season in bonobos, although data from E1 group at Wamba suggests the highest birth rate may occur during the light rainy season and just after the driest season, which may maximise the length of time after parturition before the next relatively dry season.

NEONATAL/DEVELOPMENT:

  • Newborn bonobos are immediately able to grasp their mother'' coat. They may suckle as soon as less than 10 hours after birth, or not for 24 hours.
  • The eyes and ears are open from birth; the upper edge of the ears may flop downwards initially.
  • Infant bonobos grow more slowly than do Pan troglodytes. Hand-reared infants have gained weight faster than mother-reared infants. It is estimated that in the wild, infants reach about 3 kg by three years old - only about 2.3 times their birth weight. In contrast, bottle-reared infants may reach 3 kg by six months of age. 
  • The first deciduous teeth become visible at four to six weeks of age, with temporary dentition complete at 10 months old.
  • Mother-reared bonobos remain closely attached to their mother's abdomen during the first three months and only start moving around the periphery of their mother (but still in reach) at about six months, dangling from branches and taking unsteady steps; at this age they also start mouthing food items, although actual eating of solid food starts at about one year old. Play behaviours are initially solitary; play with other infants occurs at more than one year old. At two years they are still less able than adults, but by three years their movements are similar to those of older bonobos. They are weaned at about 4-5 years. Females become independent at about seven years and disperse soon after; males also become independent but stay in the maternal community and even as adults remain in the same foraging party as their mothers.
  • Hand-reared infants have been noted to turn their heads in response to the caretaker's voice within days of birth, focus by 4 - 6 weeks, and smile at five weeks old. By six weeks it is raising itself, by seven weeks grasping purposefully and by 3.5 - 4.5 months the infant is sitting unaided; by six months they are sure-footed and climbing well. 

LITTER SIZE: Usually only one infant is born; twins are rare.

TIME BETWEEN LITTERS / LITTERS PER YEAR: The average inter-birth interval, if the first infant survives, is about five years although females return to sexual receptivity and can breed very quickly if the infant is lost (including removal for hand-rearing in captivity). Shorter inter-birth intervals do sometimes occur in the wild so that a female may have one infant on her back and a younger infant on her belly, and be suckling both of them. The shortest recorded time between live births at Wamba was one year.

LACTATION / MILK PRODUCTION: Lactation lasts about four years.

SEXUAL MATURITY: In the wild, sexual maturity is reached at about nine years in both males and females, with first births occurring when females are about 13 - 15 years old. In captivity, sexual maturity is reached earlier, with first births occurring in females only nine or ten years old.

MALE SEASONAL VARIATION: None reported.

LONGEVITY / MORTALITY: Bonobos have low infant mortality rates, with about 95% surviving to one year and more than 80% to five years. Typical life expectancy is 50-55 years.

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Life Stages (Literature Reports)

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Natural Diet

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.

NATURAL DIET: The main part of the diet is plant material, particularly fruits, but also young leaves, seeds, stalks, shoots and stems, pith, bark and flowers. Most of the diet comes from arboreal sources (trees and lianas), but terrestrial herbaceous vegetation, particularly mushrooms are eaten, as well as honey, some invertebrates (worms, termites, ants, millipedes, snails) and some vertebrates. In different bonobo populations, the vertebrates eaten differ: at Wamba, flying squirrels; at Lomako, duikers (Cephalophus spp.) and other species (e.g. snake, shrew); in the Lilungu-Lokofe region, fruit bats (Eidolon sp.) and flying squirrels. To date, primates have been confirmed as part of the diet only at Lui Kotale, Salonge National Park, with prey including adult duikers, Galago demidovii, unidentified rodents, Lophocebus aterrimus - Black mangabey, Cercopithecus ascanius - Schmidt's guenon (redtail) and Cercopithecus wolfi - Wolf's guenon; an unsuccessful hunt targeting Piliocolobus sp. - Red colobus was observed. Additionally, one instance of cannibalism has been reported in bonobos at Lui Kotale after a 2.5-year-old infant died of unknown causes.

QUANTITY EATEN: Fruits make up most of the diet (80% or more), with seeds perhaps up to 5% and leaves and other fibrous foods most of the rest of the diet. Animal material is only a very small percentage of the diet.

STUDY METHODS: Both direct observation and examination of faecal samples have been used. In some cases, evidence of feeding on certain plants (e.g. remains of plants left after feeding) have also been noted.

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Natural Diet (Literature Reports)

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Hibernation / Aestivation

EDITORIAL SUMMARY The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.

[Not applicable]

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Hibernation - Aestivation (Literature Reports)

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Haematology / Biochemistry

EDITORIAL SUMMARY
The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.
Haematology
Biochemistry

(References are available in detailed literature reports below)

CLICK THE LINKS FOR Literature Reports
Bonobo Pan paniscus - Hibernation - Aestivation (Literature Reports)

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Detailed Physiology Notes
(Summary information provided for pertinent species-specific data cross-referenced in Wildpro)

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.

METABOLISM (TEMPERATURE): There is no published data available.

RESPIRATORY SYSTEM (RESPIRATION): There is no published data available.

CIRCULATORY SYSTEM (PULSE/HEART RATE): There is no published data available.

GASTROINTESTINAL SYSTEM (FAECES AND GUT MOTILITY): There is no published data available.

URINARY SYSTEM (URINE): There are no published studies on the analysis of the normal constituents of bonobo urine, although there has been analysis of hormone levels.

CHROMOSOMES: 2n = 48

MUSCULO-SKELETAL SYSTEM: Bonobos are very strong for their size. They show definite behavioural laterality (preferring one hand over the other for particular tasks, with some being left-biased and others right-biased. They have been shown able to use precision grips, e.g. to pick up small food items, but use a tip-to-tip grip less than do humans.

SPECIAL SENSES AND VOCALISATIONS: As with the other great apes, bonobos have very good vision, including trichromatic colour vision, and they have very good hearing. They can produce a range of vocalizations, and are more vocal than the other great apes. Some of their calls are audible over long distances. The "high-hoots", audible to about 500m in forest, indicate direction and may regulate distance between individuals and parties, and allow coordination of movements between parties which are not in visual contact. Bonobos also use non-verbal communication. Use of pointing has been reported in the wild, and it has been suggested that bonobos leave signs such as flattened and broken vegetation along trains to indicate their direction of travel to other bonobos.

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Detailed Physiology Notes (Literature Reports)

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Behaviour

Feeding Behaviour

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.
  • Bonobos show a flexible foraging strategy, with the size of foraging parties varying depending on the size of available food resources. As well as taking food from trees and from the herbaceous layer, they are also known to forage in streams, marshlands and pools. They have been seen digging for earthworms and for fungi such as truffles. The largest part of the foraging time is spent eating fruits, which make up the largest part of the diet. Major fruits eaten are found in crowns of trees; bonobos will climb the tree, gather and eat food, then descend. Feeding is excited in the first 10-20 minutes after arrival at a feeding tree, then calmer and slower. To reach fruits on small branches, a bonobo will walk along a large branch and stop before the branch becomes too small to bear its weight, or disperse its weight over two or more branches, sometimes hanging most of its weight off its arms. Reaching out, it bends a branch in towards itself to take the fruit. Fruits or a branch bearing fruit may be broken off and carried a short distance in the hands, or sometimes in the mouth, a foot, or the "groin pocket", to a place where the bonobo can sit on firmer (still arboreal) substrate to eat. Mainly, fruit is taken by hand, but young bonobos occasionally take fruit straight into the mouth. Exact methods used to eat different fruits vary depending on the fruit and the character of its rind. Shoots of Megaphrynium macrostarchum and Sarcophyrnium schweinfurthii are pulled up by hand, the shoots are torn  open using the fingers and incisors and the soft pith and tender rolled-up leaf shoots are extracted and eaten.
  • Until recently, there were few records of bonobos hunting or eating meat. However, recent data indicates that hunting does occur regularly in at least some bonobo populations and that while the rate of hunting and meat eating by bonobos appears to be much lower than in some Pan troglodytes - Chimpanzee populations, it may be similar to that in other Pan troglodytes populations. Hunting of other primates has been reported from one population at Lui Kotale, Salong National Park, and an episode of cannibalism of a dead infant has been reported from the same population.
  • Drinking of water appears to be rare in the wild; bonobos probably get most of the water they need from their food. In captivity, water may be sucked or licked from various sources and a female was once seen carrying water, in her mouth, to her offspring.
  • Food sharing occurs between females and their offspring, but also between females and between males and females. Other than from mother to young, food sharing generally involves prized foods, including large fruits as well as meat. The most common response to begging is to ignore the beggar or turn away/move away, but sometimes food will be given. Copulation, or genito-genital rubbing between females, increases the chance of success in gaining food. Young females, in particular, may copulate with a male then take or receive food from him. With highly prized items, several bonobos, adults as well as immatures, may surround an adult which is in possession of the prized item, begging. Aggressive behaviour generally is not successful in gaining food.

Further information on diet is provided in Bonobo Pan paniscus - Natural Diet (Literature Reports)

(References are available in detailed literature reports below)

CLICK THE LINKS FOR Literature Reports
Bonobo Pan paniscus - Feeding Behaviour (Literature Reports)

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Parental Behaviour

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.

Female bonobos carry their infants mainly on their belly (ventrally) initially; after about two years of age it is carried mainly on her back, and it is carried during travelling to about 3-4 years of age. Bonobos probably nurse their offspring to about four years. Mothers keep their infant in reach at all times when they first start moving off their mother at a bout six months of age. They play with their infants during rest periods and are generally indulgent, and they protect their offspring against other bonobos. The bond between females and their daughters is broken in late juvenile/early adolescence, but the bond with male offspring continues, even into adulthood. When the inter-birth interval is relatively short, a female may care for, carry and suckle two dependent offspring at the same time. Other bonobos, including older male offspring and even unrelated adult males, sometimes show alloparenting, being very caring and affectionate towards infants, including playing with them, carrying them, and sharing nests and food with them, although mothers generally limit the distance the male can take the infant away from her. On one occasion when a female gave birth when her previous infant was only a year old, an adult male often cared for the older infant.

Further information on reproduction is provided in Bonobo Pan paniscus - Life Stages (Literature Reports)

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Parental Behaviour (Literature Reports)

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Social Behaviour / Territoriality / Predation / Learning

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.

Home Ranges and Distances Travelled

  • Home ranges of bonobo communities (which may include 10-120 individuals, more usually probably 30-80), vary from about 20 - 60 km², but these ranges are not exclusive: the range of a particular community may overlap with the ranges one or other communities, with only a small exclusive core area. Home ranges of communities also may change over time, as shown by observations at Wamba. Bonobos at Wamba generally travel about 0.4 - 6.0 km per day, averaging about 2.4 km per day. Data from Lomako showed that the average ranges of adult males, adult females without infants and adult females with infants were similar to one another.

Dispersal, Territoriality and Population Densities

  • Population densities vary between sites and were estimated at 0.3 - 0.9 individuals per km² at a study site west of Lake Tumba, but 1.4 - 2.5 individuals per km² at Wamba and 2 per km² along the Lomako River. Another study in the Lake Tumba area, one survey estimated population densities in different areas ranging from 0.27 per km² to 2.2 km² (upper limit of error 3.4 per km². A study at Lui Kotale, Salonga National Park, estimated bonobo population density estimates as about 0.73 weaned (nest-building) individuals per km².
  • Many areas and food resources are used by more than one community (unit group), but usually not at the same time. Observations suggest that vocal signals may be used to avoid direct confrontations and conflict, with the smaller party giving way to the larger party. Parties from different communities do sometimes come into contact with one another. These interactions are sometimes antagonistic; violent fights can occur and individual bonobos may receive injuries, but charges, mock-charges, chases and threats appear to be more common than actual physical contacts such as biting, beating, kicking or pressing down. However, non-agonistic interactions have also been observed between communities; on these occasions, males from the two communities tend not to interact with one another, but females may interact with both females and males of the other community, including intergroup female-female grooming, GG-rubbing and even copulations. Young nulliparous females tended to spend more time with individuals of the other group than with individuals of their own group during these interactions, and temporary transfer of adolescent females between groups has been observed.
  • Females are the main dispersing sex; males usually remain with their natal community, while females start moving between communities during adolescence, and settle into a new community as young adults. Results of genetic analyses are compatible with these behavioural observations.

Methods of Marking and Following Bonobos

  • Natural features, including deformities due to snare injuries, as well as natural markings, have been used to distinguish between wild bonobos. There are no reports of artificial markings being deliberately applied to aid identification.
  • Observing and following bonobos has relied on habituation. At Wamba, provisioning with sugar cane was used to speed up habituation and allow closer observation of bonobo social interactions. At other sites, provisioning has not been used for habituation.

Defensive Behaviour

  • --

Interactions with the same species

  • Bonobos live in large communities, also called "unit groups." Within a community, bonobos split up into parties or groups; this appears to enable best use of available food resources; large parties (e.g. 30 or more individuals) may be found where there is a large preferred food resource, while small parties are seen where food resources are more scattered. The members of a given party may remain stable for several days at a time, even two weeks or longer; individuals and parties from the same community may come together and split again into the same or different parties. The core social unit is a female and her offspring including adult sons (daughters leave the community). This leads to continued interaction between adult females and adult males; interactions also occur commonly between adult females, but less commonly between adult males. Most parties are mixed in age and sex, containing adult females, adult males and immature individuals. Unlike in Pan troglodytes, males do not appear to form strong alliances with one another, while females do show considerable affiliative behaviours with each other. The status of an adult male may be affected by the status and support of his mother. 
  • While bonobos do show aggressive behaviour, severe aggression as seen in Pan troglodytes does not appear to feature in bonobo society. Bonobos employ socio-sexual behaviours (copulation, non-copulatory mounting, rump-rubbing, female genito-genital rubbing and manual touching of the penis) between not only adult males and adult females but also all other possible age-sex combinations, during highly excited or tense situations; these behaviours appear to act for tension reduction and for reconciliation.

Interactions between species

  • Bonobos have been observed engaging in non-agonistic interactions with other primates, involving affiliative behaviours such as mutual touching and grooming, and play behaviours. Young bonobos have also been observed to catch and play with young monkeys, in a similar way to behaviour with infant bonobos, although without cooperation from the monkey; rough handling sometimes resulted in the death of the "toy". Bonobos do hunt other vertebrates, such as birds, squirrels and duikers, although this varies between bonobo communities: for example at Wamba, they eat flying squirrels, but not duikers, even though duikers are eaten at Lomako. At Lui Kotale, Salonga National Park, (but not so far in other locations) they have been observed hunting, killing and eating other diurnal primates. In zoos, they have been observed showing a range of behaviours towards native wildlife entering their enclosures, from curiosity to fear, and including pursuit and killing. Bonobos may play an important role in dispersing the seeds of fruit plants. 

Predation in the wild 

  • Panthera pardus - Leopard are considered to be a predator on bonobos. Stephanoaetus coronatus - Crowned hawk eagle is a known predator on adult monkeys and might predate infant Pan paniscus; Python sebae - Python also is a potential predator.

Nest Use

  • Bonobos use both day nests and night nests. A given nest might be re-used, but this is not common. Day nests are constructed more often by females than by males. Bonobos do not defecate in the nest. Night nests are built in groups reflecting congregation of bonobo parties. which forage in different areas of the home range during the day. Proximity of night nests may reflect daytime proximity of individuals, and social organisation may also be reflected in nest position, with nests of low-ranking individuals built on the periphery of the gathering. It is hypothesised that nests may provide better thermoregulation, allow more relaxed, comfortable sleeping postures, and allow sleep at sites less accessible to predators, thus permitting reduced vigilance and allowing deeper sleep. In addition to sleeping, night nests may be used for mating and possibly for other activities. Day nests are used for resting, feeding, mutual grooming and social play as well as by mother-infant pairs (with the infant often using the nest not just for rest). Nests may also be used for social functions such as a refuge for a subordinate individual, into which a dominant bonobo will not pursue it.

Intelligence and Learning

  • Bonobos are considered to be quite intelligent. They have been shown to understand mirrors, group objects by type (classify) and have an understanding of causality. An experiment involving the human-encultured bonobo Kanzi indicated good spatial memory and retention of "motivation and sense of goal direction." Data from Kanzi and other bonobos in the same research environment indicates an ability to understand language and develop simple grammatical structures, although some other researchers disagree on the interpretation of the recorded data. Spontaneous tool use has been seen in bonobos, particularly in zoos but also in the wild. In general, and particularly in the wild, bonobos appear to use tools mainly for personal care, play and social purposes, rather than for food acquisition. Females may use tools more than males. Problem-solving involving tool use has been demonstrated experimentally. Kanzi, a human-encultured bonobo, learned to knap simple stone tools, initially by demonstration but later developing his own efficient way of creating useable tools; later both he and Pan-banisha were found to produce and use a range of knapped tools for particular tasks.

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Social Behaviour - Territoriality - Predation - Learning (Literature Reports)

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Sexual Behaviour

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.
  • Female bonobos are sexually receptive for a greater proportion of the time than are female Pan troglodytes - Chimpanzees. In particular, adolescent females show prolonged receptivity, and females are sexually receptive until shortly before parturition (until about the last month of pregnancy) and return to cycling within about a year after parturition, despite not being fertile at this time. Copulation rates during oestrus are actually lower than for female Pan troglodytes
  • A variety of behaviours including approach, penile display, lead, bipedal standing, looking at and touching of the female by the male are seen prior to copulation. Bonobos copulate in both the dorso-ventral and the ventro-ventral positions, with more ventro-ventral copulations when the male involved is an adolescent, and a predominance of the ventro-dorsal position when an adult male is copulating with the female. It has been suggested that females prefer the ventro-ventral position but that adult males prefer the ventro-dorsal position. 
  • Copulation-for-food exchanges have been observed both in the wild and in zoo settings.
  • Additionally, bonobos use behaviours involving genital contact - genito-genital rubbing, non-copulatory mounting, rump-rump contact and manual touching of the penis - in the formation and maintenance of social relationships between individuals of the same or different sexes, including for reduction of tension and for reconciliation. See Bonobo Pan paniscus - Social Behaviour - Territoriality - Predation - Learning (Literature Reports) for further details.

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Sexual Behaviour (Literature Reports)

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Activity Patterns, Self-grooming and Navigation

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.

SELF-GROOMING: Bonobos spend only short periods grooming themselves or scratching themselves during grooming, while resting or after feeding. Self-scratching was also seen when a bonobo was uneasy, aware of a human observer.

CIRCADIAN RHYTHM:  Bonobos are diurnal. The basic pattern of behaviour is to rise about half an hour after sunrise (later in rain or dense fog), feed in trees, rest, move to another food patch, and repeat the pattern of feeding, resting and travelling. There are arboreal feeding peaks early in the morning and again in late afternoon, with a peak of resting around midday. They build their night nests about 40 minutes before sunset, and retire to them for the night.

SPEED OF MOVEMENT: Bonobos mainly use all four limbs for locomotion, although they do use (generally short) periods of brachiation and they also walk bipedally, mainly when using the arms for carrying, or in vigilance behaviours. Terrestrial locomotion mainly involves quadripedal knucklewalking, but bipedal walking while carrying objects has been observed. In trees, palmigrade/plantigrade quadrupedal locomotion, and quadrumanous climbing and scrambling are common; bimanual suspension is used particularly in smaller branches, and both foot-first leaping and head-first diving are used in descents. Some studies have found that females carrying infants on their bellies were less likely to use the more "risky" methods of arboreal locomotion.

NAVIGATION: A study on a a young bonobo, Kanzi, showed very good navigational ability.

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Activity Patterns, Grooming and Navigation Behaviour (Literature Reports)

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Habitat and Range

General Habitat Type

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.
  • In general, bonobos are found in moist lowland forest, including dry (terra firma) primary (mature) forest and swamp forest but also using secondary forest and swamp grasslands. They are also found in a hilly, mosaic terrain comprising dry mature forest and grasslands. 

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - General Habitat Type (Literature Reports)

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Nests / Burrows / Shelters

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.
  • Bonobos use both day nests and night nests. Day nests are often built using only one tree, and are often quite high up, while night nests are usually built about 15-30 m above ground, in the middle tree canopy and are more elaborate than day nests, using material from up to six trees; they take longer to construct. 
  • Observations at several sites have shown definite preferences regarding trees in which night nests are built; at Wamba, for example, night nests were always built in primary forest rather than secondary forest (sometimes in swamp forest when certain trees were fruiting) and bonobos sometimes moved as far as 500 m to reach suitable trees for night nesting.
  • While bonobos in all locations use nests, there are some variations. For example, bonobos at Wamba and Lomako do not build nests on the ground, while at Yalodisi and Lake Tumba, some nests are on the ground. Nests are approximately circular, and 0.3 - 1.3 m diameter.

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Nests - Burrows - Shelters (Literature Reports)

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Distribution and Movement (Migration etc.)

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.
  • Bonobos are found only in the Inner Congo Basin of the Democratic Republic of Zaire, in the area bounded in the north by the Zaire River, in the west by the Congo River, in the east by the Lualaba River and in the south by the Kasai and Sankuru Rivers. The total range is about 340,000 km2, but bonobos have a patchy distribution within this.

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Distribution & Movement (Literature Reports)

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Conservation

Species variation

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.
  • Bonobos are monotypic, with no subspecies. Now accepted as Pan paniscus, a separate species within the genus Pan, previously they had been considered only a subspecies of Pan troglodytes. However, it has also been suggested that differences are such that they should be placed in their own genus.

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Species Variation (Literature Reports)

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Conservation Status

EDITORIAL SUMMARY

The following editorial comment summarises detailed information given within the LITERATURE REPORTS. Links to the LITERATURE REPORTS are provided at the bottom of this box.

WILD POPULATION - IMPORTANCE: The total population is estimated at somewhere between 1,000 and 100,00, and declining.

GENERAL LEGISLATION: Bonobos are listed as Class A in the African Convention on the Conservation of Nature and Natural Resources and listed as Threatened under the U.S. Endangered Species Act.

CITES LISTING: Appendix I

RED-DATA LIST STATUS: Endangered under criteria A4cd (version 3.1)

THREATS: Major threats include habitat destruction and hunting - for bushmeat and for parts used in religious rituals. Even in areas where bonobos are not hunted specifically, snares can result in severe injury and loss of digits or limbs. The timber trade, by facilitating assess into the forest, and transport of both people and bushmeat, creates a market for bushmeat; forest workers often are not provided with domestic meat, so the demand for bushmeat is increased. Additionally, adults are killed to obtain infants for the illegal pet trade. Only a few areas of bonobo habitat are protected as National Parks or Reserves.

PEST STATUS / PEST POPULATIONS: --

CAPTIVE POPULATIONS: There are presently more than 200 bonobos in captive populations. Most of these are captive-born individuals in the managed populations (EEP in Europe, SSP in North America). There are also more than 50 individuals, mainly wild born orphans, at the Lola ya Bonobo sanctuary in DRC.

TRADE AND USE: Bonobos are hunted and eaten by some tribes, although others have taboos against eating bonobos. They are taken for the commercial bushmeat trade as well as for subsistence. Bonobo parts are also used in some religious rituals. Additionally, adult females may be killed to obtain infants for the [illegal] pet trade.

(References are available in detailed literature reports below)

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Bonobo Pan paniscus - Conservation Status (Literature Reports)

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