How much does it cost to look like a pig in a wild boar group?

Hybridization between domestic and wild species is known to widely occur and it is reported to be oneof the major causes of the current biodiversity crisis. Despite this, poor attention has been deserved tothe behavioural ecology of hybrids, in particular in relation to their social behaviour. We carried out acamera trap study to assess whether phenotypically anomalous colouration in wild boar, i.e. potentiallyintrogressed with domestic pigs, affected the hierarchical structure of wild boar social groups. Chromat-ically anomalous wild boars (CAWs) were detected in 32 out of 531 wild boar videos. In most videos(75%) CAWs were the latest of the group, independently from their age class and group composition.Aggressions by their wild type fellows were recorded in 31.25% videos; by contrast, no aggression amongwild type individuals was observed. The lack of camouflage may expose CAWs, and thus their group, to ahigher predation risk, compared to wild type groups. This individual loss of local adaptation may increasepredation risk by the wolf or detection by hunters, being maladaptive for the whole social group.