An animal’s ability to move around an obstacle to reach a target is called detour behaviour. To perform such task the animal must first move away from its goal to subsequently reach it. The use of an asymmetric obstacle may provide information about the animal’s spatial reasoning or spatial learning. With spatial reasoning, the subject directly chooses the shorter way, while with spatial learning it chooses the shorter way as it goes along. Our aim was to investigate detour ability in horses where we employed an asymmetric obstacle test experimental protocol. Ten Italian Saddle horses, mares (9.5±3.0 years) were used. Subjects were first accustomed to performing the detour task with a symmetric U-shaped obstacle (2×4×2m and 1m high). A breach in the obstacle permitted the passage of a food bucket through the opening. After this, one of the lateral sides of the obstacle was extended by 2m (by means of a wooden panel). A coin was tossed to decide which arm to lengthen, but it was never in the same position more than twice in subsequent trials. An operator led the horse to the bucket and left it in front of the obstacle. As the horse ate, the bucket was pulled through the obstacle. The task was considered solved if the subject reached the bucket on the other side of the obstacle within 5 min. Each subject performed ten trials on the same day, for a total of 100 tasks. The direction chosen to move around the obstacle and time employed were recorded. Time was evaluated with ANOVA, while the exact two-tails Binomial test was used to analyze the side chosen for the detour. All subjects completed the task. Six subjects showed lateralized behaviour when detouring the obstacle (three on the left and three on the right), while the other four showed no preference for either side. Non-lateralized subjects significantly chose the short side (28 out of 40 trials; z=2.37, p=0.017). The time taken to perform the task did not differ over the ten trials for the whole group (F9,90=1.259, p=0.272), for lateralized (F5,54=1.736, p=0.108) and non-lateralized horses (F3,36=0.556, p=0.820). The non-lateralized horses showed a significantly higher mean time to perform the detour compared to the lateralized horses (18.7±1.3 vs 15.9±0.7, F1,88=4.52, p=0.036). These preliminary data seem to indicate that there could be individual differences between horses when they approach spatial tasks. Some horses may use spatial reasoning to solve spatial problems and they may need more time since their behaviour is the result of a decision making procedure regarding which way is the best, while other horses showed lateralized behaviour, always going around the obstacle on the same side. Therefore, horses appear to be able to perform detour with an asymmetrical obstacle, but the solutions found could differ between subjects. Both lateralized behaviour and spatial reasoning could affect the performance when horses cope with hurdle during competitions.

### Detour behaviour with asymmetric obstacle in horses

#### Abstract

An animal’s ability to move around an obstacle to reach a target is called detour behaviour. To perform such task the animal must first move away from its goal to subsequently reach it. The use of an asymmetric obstacle may provide information about the animal’s spatial reasoning or spatial learning. With spatial reasoning, the subject directly chooses the shorter way, while with spatial learning it chooses the shorter way as it goes along. Our aim was to investigate detour ability in horses where we employed an asymmetric obstacle test experimental protocol. Ten Italian Saddle horses, mares (9.5±3.0 years) were used. Subjects were first accustomed to performing the detour task with a symmetric U-shaped obstacle (2×4×2m and 1m high). A breach in the obstacle permitted the passage of a food bucket through the opening. After this, one of the lateral sides of the obstacle was extended by 2m (by means of a wooden panel). A coin was tossed to decide which arm to lengthen, but it was never in the same position more than twice in subsequent trials. An operator led the horse to the bucket and left it in front of the obstacle. As the horse ate, the bucket was pulled through the obstacle. The task was considered solved if the subject reached the bucket on the other side of the obstacle within 5 min. Each subject performed ten trials on the same day, for a total of 100 tasks. The direction chosen to move around the obstacle and time employed were recorded. Time was evaluated with ANOVA, while the exact two-tails Binomial test was used to analyze the side chosen for the detour. All subjects completed the task. Six subjects showed lateralized behaviour when detouring the obstacle (three on the left and three on the right), while the other four showed no preference for either side. Non-lateralized subjects significantly chose the short side (28 out of 40 trials; z=2.37, p=0.017). The time taken to perform the task did not differ over the ten trials for the whole group (F9,90=1.259, p=0.272), for lateralized (F5,54=1.736, p=0.108) and non-lateralized horses (F3,36=0.556, p=0.820). The non-lateralized horses showed a significantly higher mean time to perform the detour compared to the lateralized horses (18.7±1.3 vs 15.9±0.7, F1,88=4.52, p=0.036). These preliminary data seem to indicate that there could be individual differences between horses when they approach spatial tasks. Some horses may use spatial reasoning to solve spatial problems and they may need more time since their behaviour is the result of a decision making procedure regarding which way is the best, while other horses showed lateralized behaviour, always going around the obstacle on the same side. Therefore, horses appear to be able to perform detour with an asymmetrical obstacle, but the solutions found could differ between subjects. Both lateralized behaviour and spatial reasoning could affect the performance when horses cope with hurdle during competitions.
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2011
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Utilizza questo identificativo per citare o creare un link a questo documento: `https://hdl.handle.net/11568/141557`
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