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Author Notes:

To whom correspondence may be addressed at: Joshua M. Plotnik, Department of Psychology, 532 North Kilgo Circle, Emory University, Atlanta, GA 30322; Email: jplotni@emory.edu

Frans B. M. de Waal (Email: dewaal@emory.edu)

Diana Reiss, Osborn Laboratories of Marine Sciences, New York Aquarium, Boardwalk and West 8th Street, Brooklyn, NY 11224; Email: dlr28@columbia.edu

Author contributions: J.M.P., F.B.M.d.W., and D.R. designed research; J.M.P. and D.R. performed research; J.M.P., F.B.M.d.W., and D.R. analyzed data; and J.M.P., F.B.M.d.W., and D.R. wrote the paper.

We thank Gordon Gallup, Jr., and Joyce Poole for their helpful comments on the study and manuscript.

We are grateful to J. Mahoney, P. Thomas, P. Kalk, K. Theis, G. Stark, G. Gordian, G. Fergason, W. Canino, C. Vitale, and M. Medina of the Bronx Zoo Mammal Department for their assistance in conducting the study.

We also thank R. Lattis and J. Breheny for supporting this project; the Bronx Zoo Machine and Carpentry Shops for construction of the mirror apparatus; T. Veltre, L. Groskin, J. Deveney, and D. Mulewski for audio/visual support; D. Moore, K. Payne, A. Murray, H. Lyn, and M. Maust for their assistance in this study; and J. McDowell and N. Bliwise for statistical advice.

Finally, we thank Palmer Paint Products, Inc. for providing advice on the marking material.

The authors declare no conflict of interest.


Research Funding:

This project was conducted at the Wildlife Conservation Society (WCS)'s Bronx Zoo and was supported by WCS's Living Institutions Animal Enrichment Program, the Living Links Center at the Yerkes National Primate Research Center, and the Department of Psychology at Emory University.


  • cognition
  • mirror self-recognition
  • theory of mind
  • intelligence
  • empathy

Self-recognition in an Asian elephant

Journal Title:

Proceedings of the National Academy of Sciences


Volume 103, Number 45


, Pages 17053-17057

Type of Work:

Article | Post-print: After Peer Review


Considered an indicator of self-awareness, mirror self-recognition (MSR) has long seemed limited to humans and apes. In both phylogeny and human ontogeny, MSR is thought to correlate with higher forms of empathy and altruistic behavior. Apart from humans and apes, dolphins and elephants are also known for such capacities. After the recent discovery of MSR in dolphins (Tursiops truncatus), elephants thus were the next logical candidate species. We exposed three Asian elephants (Elephas maximus) to a large mirror to investigate their responses. Animals that possess MSR typically progress through four stages of behavior when facing a mirror: (i) social responses, (ii) physical inspection (e.g., looking behind the mirror), (iii) repetitive mirror-testing behavior, and (iv) realization of seeing themselves. Visible marks and invisible sham-marks were applied to the elephants' heads to test whether they would pass the litmus “mark test” for MSR in which an individual spontaneously uses a mirror to touch an otherwise imperceptible mark on its own body. Here, we report a successful MSR elephant study and report striking parallels in the progression of responses to mirrors among apes, dolphins, and elephants. These parallels suggest convergent cognitive evolution most likely related to complex sociality and cooperation.

Copyright information:

© 2006 by The National Academy of Sciences of the USA

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