Document type: scientific synthesis published in Animal Welfare
Authors: Dijkstra PD, Oldfield RG, Kelty JD.
Abstract in French (translation): Physical enrichment and aggression in captive animals: a multi-level perspective on welfare outcomes
Aggression is one of the most serious threats to the welfare of captiveanimals, potentially leading to pain, injury, and mortality. Physical enrichment (PE), defined as the provision of physical structures and objects such as shelters, is widely used to improve well-being; however, it can also promote aggression by creating resources to defend. This perspective integrates insights from behavioral ecology and animal welfare science to develop a conceptual framework for understanding how PE influences aggression and well-being in captive animals. We propose that the combination of resource defense theory and detailed behavioral analysis constitutes a powerful tool for interpreting how environmental enrichment influences the expression of aggression and how aggression is distributed among perpetrators and targets within the group. We identify the mechanisms through which specific characteristics of enrichment (complexity, distribution, size, materials used, location) can mitigate negative consequences on well-being, notably by reducing the intensity of conflicts, providing opportunities to avoid conflicts, and redirecting behavioral motivation away from direct competition. We conclude by proposing targeted experimental approaches to isolate the effect of specific enrichment attributes on behavior and well-being. Applying this framework can inform the design of enrichment strategies that allow animals to express natural behaviors, including aggression, while minimizing negative effects on their well-being.
Preview:
Aggression is one of the most serious hazards to the welfare of captive animals, with the potential to cause pain, injury, and mortality. Physical enrichment (PE), defined as the provision of physical structures and objects such as shelters, is widely used to improve welfare, yet it can also facilitate aggression by creating defendable resources. This perspective integrates insights from behavioural ecology and animal welfare science to develop a conceptual framework for understanding how PE shapes aggression and well-being in captive animals. We propose that combining resource defence theory with detailed behavioural analysis provides a powerful tool to interpret how PE influences the expression of aggression and how it is distributed among performers and recipients within the group. We identify mechanisms through which specific attributes of enrichment (complexity, distribution, size, materials used, placement) may mitigate adverse welfare outcomes, including reducing contest intensity, providing opportunities for conflict avoidance, and diverting behavioural motivation away from direct competition. We conclude by proposing targeted experimental approaches to isolate the effect of specific enrichment attributes on behaviour and welfare. Applying this framework can inform the design of enrichment strategies that enable animals to express natural behaviours, including aggression, while minimising negative welfare outcomes.
