Table of Contents
ISRN Zoology
Volume 2011, Article ID 271209, 10 pages
http://dx.doi.org/10.5402/2011/271209
Research Article

Cooccurrence of Yawning and Stereotypic Behaviour in Horses (Equus caballus)

1UMR CNRS 6552 Ethologie Animale et Humaine, Université de Rennes 1, Campus de Beaulieu Bâtiment 25, 263 avenue du Général Leclerc, 35042 Rennes Cedex, France
2Department of Animal Behaviour, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, Postepu 1, 05 552 Wolka Kosowska, Poland

Received 21 January 2011; Accepted 10 March 2011

Academic Editors: E. Addessi and F. Colmenares

Copyright © 2011 Carole Fureix et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Determinants of yawning are still uncertain. As yawning seems to be triggered by stress and emotional contexts, we investigated specific correlates of yawning and stereotypic behaviours in horses. Study 1 investigated correlations in time between yawning and stereotypic behaviour in stereotypic horses from the same facility; study 2, involving riding school horses, investigated the cooccurrence of yawning and stereotypic behaviour at the individual level and in response to environmental factors (feeding time). Results showed that (1) stereotypic horses yawned more than the nonstereotypic horses, (2) yawning increased at the same time periods as stereotypic behaviours did, and (3) yawning frequency was positively correlated with stereotypic behaviour frequencies (study1). Different hypotheses are discussed: direct/indirect causal relationship and other factors susceptible to trigger both yawning and stereotypies. This study, underlining for the first time a cooccurrence of yawning and stereotypic behaviour, opens a promising line of investigation of this puzzling behaviour.