No evidence for contagious yawning in lemurs
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Among some haplorhine primates, including humans, relaxed yawns spread contagiously. Such contagious yawning has been linked to social bonds and empathy in some species. However, no studies have investigated contagious yawning in strepsirhines. We conducted an experimental study of contagious yawning in strepsirhines, testing ring-tailed and ruffed lemurs (n = 24) in a paradigm similar to one that has induced contagious yawning in haplorhines. First, in a control experiment, we investigated whether lemurs responded to projected video content in general (experiment 1). We showed them two videos to which we expected differential responses: one featured a terrestrial predator and the other a caretaker holding food. Next, to test for yawn contagion, we showed individual lemurs life-size video projections of groupmates and conspecific strangers yawning, and control footage of the same individuals at rest (experiment 2). Then, to examine whether a group context might enhance or allow for contagion, we exposed subjects to the same videos in a group setting (experiment 3). Lemurs produced alarm vocalizations and moved upward while viewing the predator, but not the caretaker, demonstrating that they do perceive video content meaningfully. However, lemurs did not yawn in response to yawning stimuli when tested alone, or with their groupmates. This study provides preliminary evidence that lemurs do not respond to yawning stimuli similarly to haplorhines, and suggests that this behavior may have evolved or become more exaggerated in haplorhines after the two major primate lineages split.
KeywordsContagious yawning Lemurs Strepsirhine Emotional contagion
This project would not have been possible without the help of the staff at the Duke Lemur Center, especially Dr. Erin Ehmke, David Brewer, Julie McKinney, and Meg Dye. We would also like to thank Joel Bray, Ben Finkel, Leah Kaiser, Laura Lewis, Jeremy Clift, Sruti Pisharody, and Seraphina Wong for their help with stimuli and data collection and coding. We would also like to thank Dr. Anne Pusey and Dr. Tanya Chartrand for their helpful feedback in earlier stages of this project, Aaron Sandel for his comments on the manuscript, and two anonymous reviewers for their feedback. This research was supported by a Grant from the Undergraduate Research Support office at Duke University and a Molly H. Glander Student Research Grant from the Duke Lemur Center. RBR and CK were supported by NSF GRFP DGE-1256260 and DGE-1106401, respectively.
Compliance with ethical standards
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the Institutional Animal Care and Use Committee at Duke University (Protocol # A199-11-08).
- Altmann SA (1967) Social communication among Primates. University of Chicago Press, Chicago, 325–362 Google Scholar
- Drea CM, Scordato ES (2008) Olfactory communication in the ringtailed lemur (Lemur catta): form and function of multimodal signals. In: Beynon RJ, Craig Roberts S, Wyatt TD (eds) Chemical signals in vertebrates, vol 11. Springer, Berlin, pp 91–102Google Scholar
- Harcourt AH, De Waal FB (1992) Coalitions and alliances in humans and other animals. Oxford University Press, OxfordGoogle Scholar
- Hofer H, East ML (2000) Conflict management in female-dominated spotted hyenas. In: Aureli F, de Waal F (eds) Natural conflict resolution. University of California Press, Berkeley, pp 232–234Google Scholar
- Leone A, Ferrari PF, Palagi E (2014) Different yawns, different functions? Testing social hypotheses on spontaneous yawning in Theropithecus gelada. Sci Rep 4Google Scholar
- Peterson RO, Ciucci P (2003) The wolf as a carnivore. In: Wolves: behavior, ecology, and conservation. University of Chicago Press, Chicago, pp 104–130Google Scholar
- Vasey N (2007) Impact of seasonality and reproduction on social structure, ranging patterns, and fission–fusion social organization in red ruffed lemurs. In: Gould L, Sauther ML (eds) Lemurs: ecology and adaptation. Springer, Berlin, pp 275–304Google Scholar