The responses of horses to predator stimuli

Abstract

It is not known whether the instincts of wild horses have remained strong during their centuries of domestication. Knowledge of this matter would give riders the opportunity to know more about the behavior of horses and consequently about safety for both horses and riders. In this current research, we studied the behavior of fifteen Caspian miniature horses of different ages and sexes using stimuli from predators under standardized conditions. We explored whether olfactory (lion feces) or auditory (lion roars) stimuli affected horses to a greater extent. The test arena was an appropriately equipped grass paddock, in which horses spent between 5 and 8 min. The experiments were designed to investigate behavioral responses in locomotive activity (alertness, standing, walking, trotting, exploration and other), eliminatory behavior (defecation, urination) and physiological responses (heart rates before and after the predator stimuli) of horses to novel auditory and olfactory stimuli. In the olfactory experiment, we found that the horses showed significantly more behavioral reactions compared to the control experiment (where horses were not exposed to any stimuli); the only behavioral reaction the horses did not show was flight reaction. Additionally, heart rate was significantly increased after olfactory stimuli compared to auditory stimuli. In the auditory experiment, we found that horses showed more behavioral reactions in response to the roar of the lion compared to the olfactory stimulus, including flight reactions. We concluded that the auditory stimuli caused significantly higher heart rate responses when compared to the olfactory stimuli.