Mind the gap: spatial perseveration by horses, donkeys and mules in a simple detour task

We compared spatial problem solving abilities in the mule (Equus asinus x Equus caballus) with that of its parent species to assess the effects of hybridization on cognition. In a detour task the animals(N=48) 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) and deviations from the straight line and the latency to crossing the barrier were recorded. Mules performed significantly above chance level on their first detour, unlike the other two species. We discuss our results with reference to hybrid vigour and to the flexibility of problem solving strategies with regards to species differences.