Chimpanzees

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Meet the chimpanzees of Budongo Trail


Information about chimpanzees


Species

  • The common chimpanzee is known as Pan troglodytes. Within that species, there are four different subspecies:
    • Pan troglodytes schweinfurthii (Eastern Africa)
    • Pan troglodytes troglodytes (Central Africa)
    • Pan troglodytes vellerosus, more recently phrased, Pan troglodytes ellioti (Nigeria – Cameroon) (Oates, et al., 2009)
    • Pan troglodytes verus (Western Africa)


Where they live in the wild

  • Chimpanzees have been found to live in several countries across Africa:
    • Angola, Burkina Faso, Burundi, Cameroon, Central African Republic, Congo, Côte d’Ivoire, Democratic Republic of Congo, Equatorial Guinea, Gabon, Ghana, Guinea, Guinea Bissau, Liberia, Mali, Nigeria, Rwanda (possibly extinct), Senegal, Sierra Leone, Sudan, Tanzania, and Uganda (Oates, et al., 2008)


Life stages

(Cawthon Lang, 2006)

  • Like humans, chimpanzees go through infancy, adolescence, and adulthood.
  • Life span:
    • In the wild — 40-45 years
    • In captivity — 60+ years
  • Gestation: 8 months


Group structure

  • Hierarchy
    • Chimpanzees follow a linear hierarchy where males are dominant over females and they are lead by an alpha (or dominant) male. (Goldberg & Wrangham, 1997)
  • Fission-fusion
    • They live in a fission-fusion society (Chapman, et al., 1993) where small groups (or parties) separate from and return to the larger group at various times. These small groups are likely formed to forage or hunt.


Behaviour

  • Behaviours are another way in which chimpanzees can communicate with each other. Some behaviours in particular are undeniably meaningful (Brent, et al., 1997):
    • Aggressive behaviours — chase, hit, and bite
    • Dominant behaviours — sway and display
    • Affiliative behaviours — grooming, playing, etc.
    • Submissive behaviours — fear grin, scream, and avoidance

  • Locomotion
    • Chimpanzees are quadrupedal walkers meaning that they walk on their knuckles.

  • Nest building
    • To prepare for the evening, chimpanzees build nests where they can sleep. They vary in their ability and interest in next building, with some being more involved in the process than others.

    • Chimpanzees will use a variety of materials to build their nests depending on what is available. The chimpanzees of The ChimpCam Project are given numerous materials to build their nests with straw and wood wool being highly preferred.


Communication

  • Vocalisations
    • Crucial communication tools in the dense forest when it’s not easy to see one another.
    • A few examples of vocalisations (Jane Goodall Institute, 2010)
      • Food-grunt
        • Used when feeding. Different sounds will be used high-preference food and low-preference food. (Slocombe & Zuberbüler, 2006)
      • Huu/Hoo
        • Used to stay in contact with others or when puzzled.
      • Pant-hoot
        • Used in a variety of situations, usually to indicate excitement.
        • There are four parts to the pant-hoot: introduction, build-up, climax, and let-down.
      • Scream
        • Used when angry or scared.
      • Wraa
        • Used by bystanders during a fight, often fear-related.


  • Facial expressions
    • Much like our facial expressions, they can convey a lot of information for chimpanzees.
    • Examples of facial expressions:
      • Relaxed open-mouth face
        • “The eyes and face are relaxed, but may become tense if play becomes rough. The mouth corners are in their usual position, or slightly withdrawn, but the lower lip hangs open to expose the bottom teeth. The top teeth can be slightly visible, otherwise the top lip folds over them. Vocalizations may include a fast, rhythmic staccato breathing.” (Parr, et al., 1995)
        • This is a play face
      • Fear grin or bared-teeth face
        • “The mouth may be slightly open or closed, lips withdrawn and mouth corners retracted laterally, and the teeth fully exposed.” (Parr, et al., 1995)
        • Expression varies from silent (described above) to excited.
        • This is a distressed or scared face
      • Pout
        • “Eyes are open and mouth is rounded with corners pursed forward. Lips are pursed into a round shape. No teeth are visible.” (Parr, et al., 1995)
        • Occurs with and without vocalizations.


Feeding and Foraging

(Cawthon Lang, 2006)

  • Chimpanzees are omnivores.
    • They eat a diet consisting mostly of fruit, leaves, nuts and seeds.
    • Insects and small animals are used to supplement their diet.
    • They usually spend half of their day foraging.


Intelligence

  • Intelligence can be discovered in many forms, which is why it is difficult to compare one species to another. Intelligence is best phrased in terms of each species’ abilities and needs to survive. Chimpanzees are undoubtedly intelligent animals. Here are a few of the many ways they have shown their intelligence:
    • Tool use in chimpanzees was first discovered by Jane Goodall (Goodall, 1968)
      • Fish for termites
        • Chimpanzees use blades of grass and sticks to reach inside termite mounds… if the tool was not the right shape or size, they would modify it.
      • Nut cracking (Anderson, et al., 1983; Beck, 1980; Boesch & Boesch, 1983)
        • Chimpanzees must find the perfect “anvil” and “hammer” to successfully crack a nut. The “anvil” serves as the hard work surface where the nut is placed. The “hammer” is used to strike the nut and crack it open. Each tool must be the right shape, size, and weight for the chimpanzee to be able to crack open the nut.
    • Puzzles, games, and research
      • Solving problems with “insight” instead of relying on trial and error

          — A chimpanzee reaches a banana attached to the ceiling by using items in the room. He stacked crates together to reach the ceiling.
        • Original study by Wolfgang Kohler in the 1920s (Dahl, 2005)
      • Representational use of numbers using food and objects
        • After learning how to count, a chimpanzee was able to add up 0-4 food items located in different locations.
        • Study by Sally Boysen (Boysen & Berntson, 1989)
      • Working memory (or short-term memory) of chimpanzees is much better than that of humans.
        • When numbers 1-9 are shown in random order on a screen, then covered up so they could not be seen, chimpanzees could recall the order of the numbers much faster than human competitors.
        • Study by Sana Inoue & Tetsuro Matsuzawa (Inoue & Matsuzawa, 2007)


Status



References

  • Anderson, J.R., Williamson, E.A., & Carter, J. (1983). Chimpanzees of Sapo Forest, Liberia: density, nests, tools and meat-eating. Primates 24: 594–601.

  • Beck, B.B. (1980). Animal tool behaviour: the use and manufacture of tools by animals. Garland, New York.

  • Boesch, C., Boesch, H. (1983). Optimisation of nut-cracking with naturalhammers by wild chimpanzees. Behaviour 83: 265–286.

  • Boysen, S.T. & Berntson, G.G. (1989). Numerical competence in a chimpanzee (Pan troglodytes). Journal of Comparative Psychology 103(1): 23-31.

  • Brent, L., Kessel, A.L., & Barrera, H. (1997). Evaluation of Introduction Procedures in Captive Chimpanzees. Zoo Biology 16: 335-342.

  • Cawthon Lang, K.A. (2006). Primate Factsheets: Chimpanzee (Pan troglodytes) Taxonomy, Morphology, & Ecology. http://pin.primate.wisc.edu/factsheets/entry/chimpanzee/taxon. Accessed 10 January 2010.

  • Chapman, C.A., White, F.J., & Wrangham, R.W. (1993). Defining subgroup size in fission-fusion societies. Folia Primatologica 61: 31-34.

  • Dahl, R. (2005). Psyography: Wolfgang Kohler. Accessed 10 January 2010: http://faculty.frostburg.edu/mbradley/psyography/wolfgangkohler.html).

  • Goldberg, T.L. & Wrangham, R.W. (1997). Genetic correlates of social behavior in wild chimpanzees: evidence from mitochondrial DNA. Animal Behaviour 54: 559-70.

  • Goodall, J. (1968). The behaviour of free-living chimpanzees in the Gombe Stream Reserve. Anim. Behav. Mon. 1: 161-311.

  • Inoue, S. & Matsuzawa, T. (2007). Working memory of numerals in chimpanzees. Current Biology 17(23): R1004-R1005.

  • Jane Goodall Institute. Chimp Calls. http://www.janegoodall.org/chimp-calls-0. Accessed 10 January 2010.

  • Oates, J.F., Groves, C.P., & Jenkins, P.D. (2009). The type locality of Pan troglodlytes vellerosus (Gray, 1862), and implications for the nomenclature of West African chimpanzees. Primates 50(1): 78-80.

  • Oates, J.F., Tutin, C.E.G., Humle, T., Wilson, M.L., Baillie, J.E.M., Balmforth, Z., Blom, A., Boesch, C., Cox, D., Davenport, T., Dunn, A., Dupain, J., Duvall, C., Ellis, C.M., Farmer, K.H., Gatti, S., Greengrass, E., Hart, J., Herbinger, I., Hicks, C., Hunt, K.D., Kamenya, S., Maisels, F., Mitani, J.C., Moore, J., Morgan, B.J., Morgan, D.B., Nakamura, M., Nixon, S., Plumptre, A.J., Reynolds, V., Stokes, E.J. & Walsh, P.D. 2008. Pan troglodytes. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2. . Accessed 10 January 2010.

  • Parr, L.A., Cohen, M. & de Waal, F.B.M. (2005). The influence of social context on the use of blended and graded facial displays in chimpanzees (Pan troglodytes). International Journal of Primatology 26, 73-103.

  • Slocombe, K.E. & Zuberbüler, K. (2006). Food-associated calls in chimpanzees: responses to food types or food preferences? Animal Behaviour 72(5): 989-999.