Article

The function of zebra stripes

  • Nature Communications 5, Article number: 3535 (2014)
  • doi:10.1038/ncomms4535
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Abstract

Despite over a century of interest, the function of zebra stripes has never been examined systematically. Here we match variation in striping of equid species and subspecies to geographic range overlap of environmental variables in multifactor models controlling for phylogeny to simultaneously test the five major explanations for this infamous colouration. For subspecies, there are significant associations between our proxy for tabanid biting fly annoyance and most striping measures (facial and neck stripe number, flank and rump striping, leg stripe intensity and shadow striping), and between belly stripe number and tsetse fly distribution, several of which are replicated at the species level. Conversely, there is no consistent support for camouflage, predator avoidance, heat management or social interaction hypotheses. Susceptibility to ectoparasite attack is discussed in relation to short coat hair, disease transmission and blood loss. A solution to the riddle of zebra stripes, discussed by Wallace and Darwin, is at hand.

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Acknowledgements

We thank the Chicago Field Museum, Los Angeles Natural History Museum, California Academy of Sciences, and Museum of Vertebrate Zoology at Berkeley for access to pelts, University of California for funding, and R.C.R. acknowledges funding support from the RAPIDD program of the Science and Technology Directorate, Department of Homeland Security, and the Fogarty International Center, National Institutes of Health. We thank Rickesh Patel for drawings in Fig. 1, Martin Stevens for discussion, and Brenda Larison, Tom Sherratt, Martin Stevens for comments on the manuscript.

Author information

Affiliations

  1. Department of Wildlife, Fish and Conservation Biology, University of California at Davis, 1 Shields Avenue, Davis, California 95616, USA

    • Tim Caro
    • , Amanda Izzo
    •  & Hannah Walker
  2. Center for Population Biology, University of California at Davis, 1 Shields Avenue, Davis, California 95616, USA

    • Tim Caro
  3. Department of Entomology, University of California at Davis, 1 Shields Avenue, Davis, California 95616, USA

    • Robert C. Reiner Jr
  4. Fogarty International Center, National Institutes of Health, 31 Center Drive, MSC 2220, Bethesda, Maryland 20892, USA

    • Robert C. Reiner Jr
  5. Department of Biological Sciences, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, California 90840, USA

    • Theodore Stankowich

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Contributions

T.C. conceived the project and wrote the paper; A.I. scored striping and collated range maps; B.R. digitized the range maps and quantified overlaps; H.W. collected museum pelt data; T.S. conducted the statistical analyses and provided theoretical input during data collection and manuscript preparation.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Tim Caro.

Supplementary information

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    Supplementary Information

    Supplementary Table 1, Supplementary Notes 1-4 and Supplementary References

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