SHORT COMMUNICATION Spatial cognition and perseveration by horses, donkeys and mules in a simple A-not-B detour task Britta Osthaus • Leanne Proops • Ian Hocking • Faith Burden Received: 6 September 2011 / Revised: 12 December 2012 / Accepted: 12 December 2012 / Published online: 28 December 2012 Ó Springer-Verlag Berlin Heidelberg 2012 Abstract We investigated perseveration and detour behaviour in 36 equids (Equus caballus, E. asinus, E. ca- ballus 9 E. asinus) and compared these data to those of a previous study on domestic dogs (Canis familiaris). The animals were required to make a detour through a gap at one end of a straight barrier in order to reach a visible target. After one, two, three or four repeats (A trials), the gap was moved to the opposite end of the barrier (B trials). We recorded initial deviations from the correct solution path and the latency to crossing the barrier. In the A trials, mules crossed the barrier significantly faster than their parental species, the horses and donkeys. In the B trials, following the change of gap location, all species showed a reduction in performance. Both dogs and horses exhibited significant spatial perseveration, going initially to the pre- vious gap location. Donkeys and mules, however, per- formed at chance level. Our results suggest that hybrid vigour in mules extends to spatial abilities. Keywords Equids Á Donkeys Á Horses Á Mules Á Dogs Á Detour Á Spatial reasoning Á A-not-B Á Perseveration Introduction The aim of this study was to compare the spatial abilities of mules, horses, donkeys and dogs in an initial detour task and then to assess their perseverative behaviour when the direction of the detour is changed. In a detour task, the subject must reach its goal by avoiding an intervening object, which means a straight-line solution is not possible. So far, only one study has looked into the performance of horses in a detour task (Baragli et al. 2011). Here, sym- metrical and asymmetrical U-shaped barriers were used. Horses showed a persistent side bias and did not prefer- entially use the shorter detour in the asymmetrical barrier task. There was no change in the detour time between the first and the last trial. Overall, their results indicate that horses can find their way around a U-shaped barrier, but they tend to persevere with their first route even when a shorter route becomes available. Previous research on visual reversal learning in horses has also shown that they have difficulties inhibiting a learned response (Sappington et al. 1997). Donkeys are also able to navigate a barrier (Baragli and Regolin 2008). To our knowledge, mules have not yet been tested on a detour task. The tendency to maintain a previous route despite the availability of a better one has also been found in dogs (Osthaus et al. 2010). In this study, dogs were able to solve simple detour tasks but persevered with a previously learned route even if this was visibly blocked and even after they had navigated through the new gap several times. This tendency to approach a previously successful location despite obvious visual signs that the location has now been changed is also seen in dogs when locating hidden rewards (Ga ´csi et al. 2009) and is called the A-not-B error, a phe- nomenon first described in human infants (Piaget 1954, p. 44). In this study, we assess for the first time the spatial abilities and perseveration behaviour of horses, donkeys and mules in an A-not-B detour task and compare their responses to those of domestic dogs. The mule, the hybrid B. Osthaus (&) Á I. Hocking Psychology, Canterbury Christ Church University, Canterbury CT1 1QU, UK e-mail: britta.osthaus@canterbury.ac.uk L. Proops Psychology, University of Sussex, Falmer, UK F. Burden Donkey Sanctuary, Sidmouth, UK 123 Anim Cogn (2013) 16:301–305 DOI 10.1007/s10071-012-0589-4