UC Davis

Domestic horses and ponies communicate using visual and auditory signals. It has been reported that equines can respond to visual cues in object-choice tests, but utilization of auditory cues, alone or associated with visual cues, has not be investigated. Effect of equine breed type in object-choice selection is unknown. Using object-choice tests, we investigated the hypotheses that breed types (1) can use both visual and auditory human-given cues; (2) that performance is enhanced when both visual and auditory cues are presented together to signal a baited bucket, compared with when a cue is presented singly; (3) that latency to make a choice increases and choice is random, when auditory and visual cues conflict; and (4) that ponies outperform horses. Irrespective of breed type, subjects were equally successful at using single visual, auditory, and combined cues (proportion of correct choices: visual 0.63 ± 0.047 [P =004], auditory 0.61 ± 0.045 [P =013], combined 0.64 ± 0.054 [P =007]). In contrast to our hypothesis, combining cues did not significantly improve the likelihood of correct choice. Ponies outperformed horses using visual cues (P =044). In conflicting cue tests, 70% of subjects responded randomly; the remainder preferentially responded to visual cues. Our study showed that horses and ponies can respond with equal proficiency to both visual and auditory cues, alone and combined; however, ponies outperformed horses using visual cues. Our results may be used to improve relationships between humans and equines, as we demonstrated the importance of engaging both visual and auditory modalities.