Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Lethal aggression in Pan is better explained by adaptive strategies than human impacts

Nature volume 513, pages 414–417 (2014)Cite this article

Subjects

Abstract

Observations of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) provide valuable comparative data for understanding the significance of conspecific killing. Two kinds of hypothesis have been proposed. Lethal violence is sometimes concluded to be the result of adaptive strategies, such that killers ultimately gain fitness benefits by increasing their access to resources such as food or mates1,2,3,4,5. Alternatively, it could be a non-adaptive result of human impacts, such as habitat change or food provisioning6,7,8,9. To discriminate between these hypotheses we compiled information from 18 chimpanzee communities and 4 bonobo communities studied over five decades. Our data include 152 killings (n = 58 observed, 41 inferred, and 53 suspected killings) by chimpanzees in 15 communities and one suspected killing by bonobos. We found that males were the most frequent attackers (92% of participants) and victims (73%); most killings (66%) involved intercommunity attacks; and attackers greatly outnumbered their victims (median 8:1 ratio). Variation in killing rates was unrelated to measures of human impacts. Our results are compatible with previously proposed adaptive explanations for killing by chimpanzees, whereas the human impact hypothesis is not supported.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Number of victims killed per year by members of study communities.
Figure 2: Number of killings per year for each community versus number of males and population density.

Similar content being viewed by others

References

  1. Goodall, J. The Chimpanzees of Gombe: Patterns of Behavior (Belknap Press, 1986)

    Google Scholar 

  2. Wrangham, R. W. Evolution of coalitionary killing. Am. J. Phys. Anthropol. 110, (suppl.) 1–30 (1999)

    Google Scholar 

  3. Wilson, M. L. & Wrangham, R. W. Intergroup relations in chimpanzees. Annu. Rev. Anthropol. 32, 363–392 (2003)

    Google Scholar 

  4. Boesch, C. The Real Chimpanzee: Sex Strategies in the Forest (Cambridge Univ. Press, 2009)

    Google Scholar 

  5. Mitani, J. C., Watts, D. P. & Amsler, S. J. Lethal intergroup aggression leads to territorial expansion in wild chimpanzees. Curr. Biol. 20, R507–R508 (2010)

    CAS  PubMed  Google Scholar 

  6. Power, M. The Egalitarians—Human and Chimpanzee: An Anthropological View of Social Organization (Cambridge Univ. Press, 1991)

    Google Scholar 

  7. Sussman, R. W. in War, Peace, and Human Nature: The Convergence of Evolutionary and Cultural Views (ed. Fry, D. P. ) 97–111 (Oxford Univ. Press, 2013)

    Google Scholar 

  8. Ferguson, R. B. in Origins of Altruism and Cooperation (eds Sussman, R. W. & Cloninger, C. R. ). 249–270 (2011)

  9. Bartlett, T. Q., Sussman, R. W. & Cheverud, J. M. Infant killing in primates: a review of observed cases with specific reference to the sexual selection hypothesis. Am. Anthropol. 95, 958–990 (1993)

    Google Scholar 

  10. Mitani, J. C. Cooperation and competition in chimpanzees: current understanding and future challenges. Evol. Anthropol. 18, 215–227 (2009)

    Google Scholar 

  11. Boesch, C. et al. Intergroup conflicts among chimpanzees in Tai National Park: lethal violence and the female perspective. Am. J. Primatol. 70, 519–532 (2008)

    PubMed  Google Scholar 

  12. Wrangham, R. W., Wilson, M. L. & Muller, M. N. Comparative rates of violence in chimpanzees and humans. Primates 47, 14–26 (2006)

    PubMed  Google Scholar 

  13. Williams, J. M., Oehlert, G., Carlis, J. & Pusey, A. E. Why do male chimpanzees defend a group range? Reassessing male territoriality. Anim. Behav. 68, 523–532 (2004)

    Google Scholar 

  14. Mitani, J. C. Demographic influences on the behavior of chimpanzees. Primates 47, 6–13 (2006)

    PubMed  Google Scholar 

  15. Fawcett, K. & Muhumuza, G. Death of a wild chimpanzee community member: possible outcome of intense sexual competition. Am. J. Primatol. 51, 243–247 (2000)

    CAS  PubMed  Google Scholar 

  16. Watts, D. P. Intracommunity coalitionary killing of an adult male chimpanzee at Ngogo, Kibale National Park, Uganda. Int. J. Primatol. 25, 507–521 (2004)

    Google Scholar 

  17. Pusey, A. E. et al. Severe aggression among female Pan troglodytes schweinfurthii at Gombe National Park, Tanzania. Int. J. Primatol. 29, 949–973 (2008)

    Google Scholar 

  18. Hamilton, W. D. The genetical evolution of social behavior. I, II. J. Theor. Biol. 7, 1–16 (1964)

    CAS  PubMed  Google Scholar 

  19. Maynard Smith, J. The theory of games and the evolution of animal conflicts. J. Theor. Biol. 47, 209–221 (1974)

    MathSciNet  Google Scholar 

  20. Prado-Martinez, J. et al. Great ape genetic diversity and population history. Nature 499, 471–475 (2013)

    ADS  CAS  PubMed  PubMed Central  Google Scholar 

  21. Boesch, C., Hohmann, G. & Marchant, L. F. Behavioral Diversity in Chimpanzees and Bonobos (Cambridge Univ. Press, 2002)

    Google Scholar 

  22. Burnham, K. P. & Anderson, D. R. Model Selection and Multimodel Inference: A Practical Information-Theoretic Approach. 2nd edn, xxvi, 488 (Springer, 2002)

    MATH  Google Scholar 

  23. Potts, K. B., Watts, D. P. & Wrangham, R. W. Comparative feeding ecology of two communities of chimpanzees (Pan troglodytes) in Kibale National Park, Uganda. Int. J. Primatol. 32, 669–690 (2011)

    Google Scholar 

  24. Emery Thompson, M., Muller, M. N., Wrangham, R. W., Lwanga, J. S. & Potts, K. B. Urinary C-peptide tracks seasonal and individual variation in energy balance in wild chimpanzees. Horm. Behav. 55, 299–305 (2009)

    PubMed  Google Scholar 

  25. Sponheimer, M. et al. Do “savanna” chimpanzees consume C-4 resources? J. Hum. Evol. 51, 128–133 (2006)

    CAS  PubMed  Google Scholar 

  26. Inoue, E., Inoue-Murayama, M., Vigilant, L., Takenaka, O. & Nishida, T. Relatedness in wild chimpanzees: influence of paternity, male philopatry, and demographic factors. Am. J. Phys. Anthropol. 137, 256–262 (2008)

    PubMed  Google Scholar 

  27. Wilson, M. L., Kahlenberg, S. M., Wells, M. T. & Wrangham, R. W. Ecological and social factors affect the occurrence and outcomes of intergroup encounters in chimpanzees. Anim. Behav. 83, 277–291 (2012)

    Google Scholar 

  28. Bishop, N., Hrdy, S. B., Teas, J. & Moore, J. Measures of human influence in habitats of South Asian monkeys. Int. J. Primatol. 2, 153–167 (1981)

    Google Scholar 

  29. R: A language and environment for statistical computing v. 3.0.2 (R Foundation for Statistical Computing, Vienna, Austria, 2013)

  30. Field, A. Discovering Statistics Using SPSS (Sage Publications, 2005)

    MATH  Google Scholar 

  31. Bolker, B., Skaug, H., Magnusson, A. & Nielsen, A. Getting started with the glmmADMB package <http://glmmadmb.r-forge.r-project.org/glmmADMB.html> (2012)

    Google Scholar 

  32. Bates, D., Maechler, M., Bolker, B. & Walker, S. lme4: Linear mixed-effects models using Eigen and S4. R package version 1. 0-5, <http://www.inside-r.org/packages/lme4/versions/1-0-5> (2013)

  33. Schielzeth, H. & Forstmeier, W. Conclusions beyond support: overconfident estimates in mixed models. Behav. Ecol. 20, 416–420 (2009)

    PubMed  Google Scholar 

  34. Barr, D. J., Levy, R., Scheepers, C. & Tily, H. J. Random effects structure for confirmatory hypothesis testing: Keep it maximal. J. Mem. Lang. 68, 255–278 (2013)

    Google Scholar 

  35. Wilson, M. L., Wallauer, W. & Pusey, A. E. New cases of intergroup violence among chimpanzees in Gombe National Park, Tanzania. Int. J. Primatol. 25, 523–549 (2004)

    Google Scholar 

  36. Williams, J. M. et al. Causes of death in the Kasekela chimpanzees of Gombe National Park, Tanzania. Am. J. Primatol. 70, 766–777 (2008)

    CAS  PubMed  Google Scholar 

  37. Watts, D. P., Muller, M., Amsler, S. J., Mbabazi, G. & Mitani, J. C. Lethal intergroup aggression by chimpanzees in Kibale National Park, Uganda. Am. J. Primatol. 68, 161–180 (2006)

    PubMed  Google Scholar 

  38. Wrangham, R. W. The Behavioural Ecology of Chimpanzees in Gombe National Park, Tanzania. Ph.D. thesis, Cambridge University (1975)

    Google Scholar 

  39. Hashimoto, C. & Furuichi, T. Possible intergroup killing in chimpanzees in the Kalinzu Forest, Uganda. Pan Africa News 12, 3–5 (2005)

    Google Scholar 

  40. Muller, M. N. in Behavioural Diversity in Chimpanzees and Bonobos (eds C. Boesch, G. Hohmann & L. F. Marchant ) 112–123 (Cambridge Univ. Press, 2002)

    Google Scholar 

  41. Nishida, T., Hiraiwa-Hasegawa, M., Hasegawa, T. & Takahata, Y. Group extinction and female transfer in wild chimpanzees in the Mahale National Park, Tanzania. Z. Tierpsychol. 67, 284–301 (1985)

    Google Scholar 

  42. Newton-Fisher, N. E. Infant killers of Budongo. Folia Primatol. 70, 167–169 (1999)

    CAS  Google Scholar 

  43. Townsend, S. W., Slocombe, K. E., Emery Thompson, M. & Zuberbuhler, K. Female-led infanticide in wild chimpanzees. Curr. Biol. 17, R355–R356 (2007)

    CAS  PubMed  Google Scholar 

  44. Bygott, J. D. Cannibalism among wild chimpanzees. Nature 238, 410–411 (1972)

    ADS  Google Scholar 

  45. Goodall, J. Infant killing and cannibalism in free-living chimpanzees. Folia Primatol. 28, 259–282 (1977)

    CAS  Google Scholar 

  46. Watts, D. P. & Mitani, J. C. Infanticide and cannibalism by male chimpanzees at Ngogo, Kibale National Park, Uganda. Primates 41, 357–365 (2000)

    PubMed  Google Scholar 

  47. Watts, D. P., Mitani, J. C. & Sherrow, H. M. New cases of inter-community infanticide by male chimpanzees at Ngogo, Kibale National Park, Uganda. Primates 43, 263–270 (2002)

    PubMed  Google Scholar 

  48. Sherrow, H. M. & Amsler, S. J. New intercommunity infanticides by the chimpanzees of Ngogo, Kibale National Park, Uganda. Int. J. Primatol. 28, 9–22 (2007)

    Google Scholar 

  49. Kutsukake, N. & Matsusaka, T. Incident of intense aggression by chimpanzees against an infant from another group in Mahale Mountains National Park, Tanzania. Am. J. Primatol. 58, 175–180 (2002)

    PubMed  Google Scholar 

  50. Nishida, T., Uehara, S. & Nyundo, R. Predatory behavior among wild chimpanzees of the Mahale mountains. Primates 20, 1–20 (1979)

    Google Scholar 

  51. Kaburu, S. S. K., Inoue, S. & Newton-Fisher, N. E. Death of the alpha: within-community lethal violence among chimpanzees of the Mahale Mountains National Park. Am. J. Primatol. 75, 789–797 (2013)

    PubMed  Google Scholar 

  52. Watts, D. P. Intracommunity coalitionary killing of an adult male chimpanzee at Ngogo, Kibale National Park, Uganda. Int. J. Primatol. 25, 507–521 (2004)

    Google Scholar 

  53. Fawcett, K. & Muhumuza, G. Death of a wild chimpanzee community member: possible outcome of intense sexual competition. Am. J. Primatol. 51, 243–247 (2000)

    CAS  PubMed  Google Scholar 

  54. Nishida, T. Chimpanzees of the Lakeshore: Natural History and Culture at Mahale. (Cambridge Univ. Press, 2012)

    Google Scholar 

  55. Hohmann, G. & Fruth, B. in Among African Apes: Stories and Photos from the Field (eds Martha M. Robbins & Christophe Boesch ) (Univ. of California Press, 2011)

    Google Scholar 

  56. Hobaiter, C. Gestural communication in wild chimpanzees. Ph.D. thesis. thesis, University of St Andrews, Scotland (2010)

    Google Scholar 

  57. Murray, C. M., Wroblewski, E. & Pusey, A. E. New case of intragroup infanticide in the chimpanzees of Gombe National Park. Int. J. Primatol. 28, 23–37 (2007)

    Google Scholar 

  58. Hamai, M., Nishida, T., Takasaki, H. & Turner, L. New records of within-group infanticide and cannibalism in chimpanzees. Primates 33, 151–162 (1992)

    Google Scholar 

  59. Takahata, Y. Adult male chimpanzees kill and eat a newborn infant: newly observed intragroup infanticide and cannibalism in Mahale National Park, Tanzania. Folia Primatol. 44, 161–170 (1985)

    Google Scholar 

  60. Arcadi, A. C. & Wrangham, R. W. Infanticide in chimpanzees: review of cases and a new within-group observation from the Kanyawara study group in Kibale National Park. Primates 40, 337–351 (1999)

    Google Scholar 

  61. Pusey, A. E. et al. Severe aggression among female Pan troglodytes schweinfurthii at Gombe National Park, Tanzania. Int. J. Primatol. 29, 949–973 (2008)

    Google Scholar 

  62. Boesch, C. & Boesch-Achermann, H. The Chimpanzees of the Taï Forest: Behavioral Ecology and Evolution (Oxford Univ. Press, 2000)

    Google Scholar 

  63. Norikoshi, K. One observed case of cannibalism among wild chimpanzees of the Mahale Mountains. Primates 23, 66–74 (1982)

    Google Scholar 

  64. Kawanaka, K. Infanticide and cannibalism with special reference to the newly observed case in the Mahale Mountains. Afr. Study Monogr. 1, 69–99 (1981)

    Google Scholar 

  65. Hiraiwa-Hasegawa, M., Hasegawa, T. & Nishida, T. Demographic study of a large-sized unit-group of chimpanzees in the Mahale Mountains, Tanzania: A preliminary report. Primates 25, 401–413 (1984)

    Google Scholar 

  66. Nishida, T. & Kawanaka, K. Within-group cannibalism by adult male chimpanzees. Primates 26, 274–284 (1985)

    Google Scholar 

  67. Hosaka, K., Matsumoto-Oda, A., Huffman, M. A. & Kawanaka, K. Reactions to dead bodies of conspecifics by wild chimpanzees in the Mahale Mountains, Tanzania. Primate Res. 16, 1–15 (2000)

    Google Scholar 

Download references

Acknowledgements

This study was funded by National Science Foundation grants BCS-0648481 and LTREB-1052693 and National Institutes of Health grant R01 AI 058715. Numerous additional sources of funding have supported the long-term studies that contributed data to this study. We thank J. H. Jones for statistical advice; L. Pintea for preparing the map for Extended Data Fig. 1b; I. Lipende and R. Lawrence for providing details on recent cases at Gombe and Kanyantale; S. Amsler for helping to calculate the range of the Kanyantale community, and the many field assistants who collected data.

Author information

Authors and Affiliations

  1. Department of Anthropology, University of Minnesota, 395 Humphrey Center, 301 19th Avenue South, Minneapolis, Minnesota 55455, USA,

    Michael L. Wilson

  2. Department of Ecology, Evolution and Behavior, University of Minnesota, 1987 Upper Buford Circle, St Paul, Minnesota 55108, USA,

    Michael L. Wilson

  3. Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany,

    Christophe Boesch, Gottfried Hohmann, Julia Riedel & Roman M. Wittig

  4. Division of Neurobiology, Ludwig-Maximilians Universitaet Muenchen, Germany

    Barbara Fruth

  5. Centre for Research and Conservation, Royal Zoological Society of Antwerp, Belgium

    Barbara Fruth

  6. Primate Research Institute, Kyoto University, 41-2 Kanrin, Inuyama, Aichi 484-8506, Japan,

    Takeshi Furuichi, Chie Hashimoto & Tetsuro Matsuzawa

  7. Department of Evolutionary Anthropology, Duke University, 104 Biological Sciences Building, Box 90383, Durham, North Carolina 27708-0680, USA,

    Ian C. Gilby & Anne E. Pusey

  8. School of Human Evolution and Social Change, Arizona State University, PO Box 872402, Tempe, Arizona 85287-2402, USA,

    Ian C. Gilby

  9. School of Psychology and Neuroscience, University of St Andrews, Westburn Lane, St Andrews, Fife KY16 9JP, UK,

    Catherine L. Hobaiter & Klaus Zuberbühler

  10. Wildlife Research Center, Kyoto University, 2-24 Tanaka-Sekiden-Cho, Sakyo, Kyoto, Japan,

    Noriko Itoh & Michio Nakamura

  11. Division of Biological Anthropology, Department of Archaeology & Anthropology, University of Cambridge, Henry Wellcome Building, Fitzwilliam Street, Cambridge CB2 1QH, UK,

    Kathelijne Koops

  12. Zoology Department, Makerere University, P.O. Box 7062, Kampala, Uganda,

    Julia N. Lloyd & Nicole Simmons

  13. Japan Monkey Center, 26 Kanrin, Inuyama, Aichi 484-0081, Japan,

    Tetsuro Matsuzawa

  14. Department of Anthropology, University of Michigan, 101 West Hall, 1085 S. University Avenue, Ann Arbor, 48109, Michigan, USA

    John C. Mitani

  15. Gombe Stream Research Centre, The Jane Goodall Institute – Tanzania, P.O. Box 1182, Kigoma, Tanzania,

    Deus C. Mjungu

  16. The Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, Chicago, 60614, Illinois, USA

    David Morgan

  17. Department of Anthropology, MSC01-1040, Anthropology 1, University of New Mexico, Albuquerque, 87131, New Mexico, USA

    Martin N. Muller

  18. Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany,

    Roger Mundry

  19. Department of Anthropology, Iowa State University, 324 Curtiss, Ames, Iowa 50011, USA,

    Jill Pruetz

  20. Department of Anthropology, Washington University in St Louis, Campus Mailbox 1114, One Brookings Drive, St Louis, Missouri 63130, USA,

    Crickette Sanz

  21. Department of Psychology, University of York, Heslington, York, YO10 5DD, UK,

    Anne M. Schel

  22. Department of Anthropology, University of Oregon, Eugene, 97403, Oregon, USA

    Michel Waller & Frances White

  23. Department of Anthropology, Yale University, 10 Sachem Street, New Haven, Connecticut 06511, USA,

    David P. Watts

  24. Université de Neuchâtel, Institut de Biologie, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland,

    Klaus Zuberbühler

  25. Department of Human Evolutionary Biology, Harvard University, 11 Divinity Avenue Cambridge, Massachusetts 02138, USA,

    Richard W. Wrangham

Authors
  1. Michael L. Wilson
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Christophe Boesch
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Barbara Fruth
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Takeshi Furuichi
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Ian C. Gilby
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Chie Hashimoto
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Catherine L. Hobaiter
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Gottfried Hohmann
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Noriko Itoh
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Kathelijne Koops
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Julia N. Lloyd
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Tetsuro Matsuzawa
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. John C. Mitani
    View author publications

    You can also search for this author in PubMed Google Scholar

  14. Deus C. Mjungu
    View author publications

    You can also search for this author in PubMed Google Scholar

  15. David Morgan
    View author publications

    You can also search for this author in PubMed Google Scholar

  16. Martin N. Muller
    View author publications

    You can also search for this author in PubMed Google Scholar

  17. Roger Mundry
    View author publications

    You can also search for this author in PubMed Google Scholar

  18. Michio Nakamura
    View author publications

    You can also search for this author in PubMed Google Scholar

  19. Jill Pruetz
    View author publications

    You can also search for this author in PubMed Google Scholar

  20. Anne E. Pusey
    View author publications

    You can also search for this author in PubMed Google Scholar

  21. Julia Riedel
    View author publications

    You can also search for this author in PubMed Google Scholar

  22. Crickette Sanz
    View author publications

    You can also search for this author in PubMed Google Scholar

  23. Anne M. Schel
    View author publications

    You can also search for this author in PubMed Google Scholar

  24. Nicole Simmons
    View author publications

    You can also search for this author in PubMed Google Scholar

  25. Michel Waller
    View author publications

    You can also search for this author in PubMed Google Scholar

  26. David P. Watts
    View author publications

    You can also search for this author in PubMed Google Scholar

  27. Frances White
    View author publications

    You can also search for this author in PubMed Google Scholar

  28. Roman M. Wittig
    View author publications

    You can also search for this author in PubMed Google Scholar

  29. Klaus Zuberbühler
    View author publications

    You can also search for this author in PubMed Google Scholar

  30. Richard W. Wrangham
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

All authors contributed to the acquisition, analysis and interpretation of the data; M.L.W., R.W.W., and J.C.M. initiated and conceived the study; M.L.W. and R.M. performed statistical analyses; C.B., B.F., T.F., C.H., C.L.H., G.H., N.I., K.K., J.N.L., T.M., J.C.M., D.C.M., D.M., M.N.M., M.N., J.P., A.E.P., C.S., N.S., D.P.W., F.W., K.Z., M.L.W., R.M.W., and R.W.W. conducted and supervised fieldwork; C.B., T.F., I.C.G., C.H., C.L.H., G.H., J.N.L., T.M., J.C.M., D.C.M., D.M., M.N.M., M.N., J.P., J.R., C.S., A.M.S., N.S., M.L.W., M.W., D.P.W., F.W., R.W.W. and K.Z. provided demographic and ranging data; C.B., T.F., C.H., G.H., J.N.L., T.M., J.C.M., M.N., J.P., A.E.P., N.S., F.W., M.L.W., R.W.W., and K.Z. provided data on site characteristics and human disturbance ratings; M.L.W. coordinated the contributions of all authors; M.L.W. wrote the paper with J.C.M., D.P.W., R.W.W. and input from all authors.

Corresponding author

Correspondence to Michael L. Wilson.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Extended data figures and tables

Extended Data Figure 1 Summary data and location of study sites.

a, Summary data for each community. Clade: bonobos (B), eastern chimpanzees (E), western chimpanzees (W); community: mean total size of the community; males: mean number of males ≥ 12 years old; females: mean number of females ≥ 12 years old; home range: mean size of the community’s home range (km2); density = (community)/(home range); area: size of protected area inhabited by the community; provisioned: whether community was regularly provisioned with food; disturbance: sum of the disturbance rating scores. b, Location of chimpanzee (circles; n = 10) and bonobo (squares; n = 3) study sites in Africa.

Extended Data Figure 2 Disturbance ratings.

a, Disturbance ratings for each site: disturbance to habitat (black bars); harassment of study animals by people (vertical lines); amount of hunting of study animals (grey); degree of habituation to people at start of study (diagonal hatching); and whether major predators have been eliminated (white). Clade is indicated by letters following community name: bonobos (B), eastern chimpanzees (E), and western chimpanzees (W). b, Number of killings per year vs. disturbance. Rates for each community are indicated by black diamonds (chimpanzees; n = 18) and open squares (bonobos; n = 4).

Extended Data Table 1 Intercommunity killings of weaned victims
Full size table
Extended Data Table 2 Intercommunity infanticides
Full size table
Extended Data Table 3 Intracommunity killings of weaned victims
Full size table
Extended Data Table 4 Intracommunity infanticides
Full size table
Extended Data Table 5 Summary of model averaged parameters using different subsets of the data
Full size table
Extended Data Table 6 Summary of parameter estimates for test of the effect of age and sex on probability of being killed
Full size table
Extended Data Table 7 Number of attackers and defenders on each side for intercommunity killings
Full size table

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Wilson, M., Boesch, C., Fruth, B. et al. Lethal aggression in Pan is better explained by adaptive strategies than human impacts. Nature 513, 414–417 (2014). https://doi.org/10.1038/nature13727

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature13727

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing