Information gathering during contests: The relationship between lateralisation and contestant behaviour during fallow deer fights

One class of model relating to animal contest behaviour assumes that individuals gather information concerning their opponents' competitive ability; these models argue that such a process allows contestants to avoid engaging in dangerous fighting behaviour with a superior opponent. The brain hemispheres of vertebrates are lateralised in that they are specialised for processing different type of information. Within the context of the current study, we might expect that lateralisation would play a role in facilitating the assessment of opponent quality; nevertheless, the degree of lateralisation shown by individuals can vary suggesting that contest behaviour might also vary based on the ability to process information about competitor quality. The current study tests this hypothesis by predicting that the duration that individuals engage in fighting and the rate of aggressive contest actions should decrease as lateralisation increases. There was a positive relationship between two laterality indices and the duration spent in antler contact; thus lateralised individuals experienced greater time costs. Further, lateralised individuals also experienced a greater disparity in contest actions: there was a negative relationship between lateralisation and the difference in the mean number of backward pushes achieved during fights. When only opponent signal rate was considered there was no effect of lateralisation, therefore, there is support for a mutual assessment process. These results suggest that information gathering via lateral displays may be disadvantageous to lateralised individuals during escalated fighting.