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

Carole Fureix,Martine Hausberger,Emmanuel Gautier,Aleksandra Gorecka-Bruzda

doi:10.5402/2011/271209

Carole Fureix, Martine Hausberger + Show 2 more

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https://doi.org/10.5402/2011/271209

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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.

Highlights

A yawn is an involuntary sequence consisting in mammals of mouth opening, deep inspiration, brief apnoea, and slow expiration [1] and is especially frequent in humans and carnivores, for example, [2, 3]
Yawning can be triggered by stress and emotional contexts
Yawning increased at the same time periods as stereotypic behaviours did, and its frequency was, in the first study, correlated with stereotypic behaviour frequencies: the more frequent their stereotypic behaviours were displayed, the more frequently the horses yawned

Summary

Introduction

A yawn is an involuntary sequence consisting in mammals of mouth opening, deep inspiration, brief apnoea, and slow expiration [1] and is especially frequent in humans and carnivores, for example, [2, 3]. The fact that yawning is involved in behavioural state changes is well established, especially in quiet contexts of motor relaxation such as before or just after sleep, see for example, [1,2,3, 6,7,8]. Reamer et al [16] exploring correlates of selfdirected behaviour and “abnormal” stereotypic behaviour, prevalent in stress-inducing environments (e.g., [17]) in captive red-capped mangabeys (Cercocebus torquatus torquatus), failed to evidence a relationship between yawning and stereotypic behaviour. Their analysis did not separate yawning from other self-directed behaviours (i.e., self-scratching, self-grooming, and body shaking)

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