Reactions to objects and humans in Przewalski's horses: a first step to assess domestication effects on behaviour in horses

Sammanfattning: Despite the increasing interest in equine science little research has focused on possible differences in behaviour between domestic horses and their wild ancestors. Understanding if or how domestication has changed horse behaviour, along with better comprehension of behavioural differences in equine species, can improve housing, handling and training of equids as well as increase the safety of their human handlers. The wild progenitors of today’s domestic horses are now extinct, but the Przewalksi's horse could serve as an alternative when we want to compare the behaviour of the domestic horse with a wild equid. The aim of this study was to develop and evaluate tests that can be used on both domestic and wild equids, in order to examine fear reactions, social transmission of behaviour and reactions to novel objects and humans. For this purpose, we need tests that can be conducted on groups of individuals held in zoos or similar domestic settings. It is important to be able to test equids in groups as separating them from their social group for testing can lead to misleading results. A group of 3 Przewalski's horses housed in a zoo environment were used in this study. Three tests were applied: 1) a novel object test, where the horses were exposed to a familiar and an unfamiliar object, 2) a voluntary approach test, where the horses were exposed to a familiar and an unfamiliar human, and 3) a target training test, where one individual, while remaining in the group, was trained with positive reinforcement to touch a target. Individual variation was evident, despite the horses being tested together. This suggests that group testing does not introduce a significant bias to individual differences in behaviour, and provides an alternative to isolate individuals in future tests. The horses showed different behaviours depending on if the object or human was familiar to them or not, and signs of habituation to the novel stimuli were noted. During the target training the horse was active, attentive and learned the behaviour instantly. Tests that have been used to show domestication effects in dogs have also been used on horses, but I question their relevance since the dog has had a different role as a human companion. Instead I suggest similar tests as the ones in this study to be used on different equine species in order to extend the knowledge of variation and similarity in equine behaviour.