Are free-ranging Kune Kune pigs (Sus scrofa domesticus) able to solve a cooperative task?

Abstract Cooperative behaviour has been observed in many species and in several domains like cooperative hunting, cooperative predator defence and cooperative breeding. From an evolutionary perspective, it is an efficient way to increase one’s own success, which ultimately has positive fitness consequences. However, the underlying mechanism in terms of the motivational and cognitive processes is less clear. Pigs are cooperative breeders, highly sociable and possess advanced skills in various cognitive domains and sensory modalities. The aim of this study was to explore whether domestic pigs would cooperate to acquire resources. We tested this using the Joint-Log-Lift task, which requires that two pigs lift a wooden log simultaneously to obtain food. Ten same-sex dyads of free-ranging Kune Kune pigs were tested. They did not interact with the apparatus in at least one of a six-trial session and hence, did not solve the task spontaneously, but became successful after several training steps including both individual and partner training. Because the Joint-Log-Lift task requires behavioural coordination to be solved cooperatively and efficiently, we tested the pigs’ understanding of the need for coordination in two classical tests. A 10 or 30 s delay condition tested whether the pig who was released earlier into the testing arena would wait for the partner before lifting the log. A visual barrier condition tested whether the inability to see the partner would reduce the synchronicity of their actions toward the log. The dyads did not respond differently in the two testing manipulations, therefore failing to show evidence for coordinated behaviour. We discussed these findings in terms of weak understanding of the cooperative requirements of the task, disadvantageous training and low impulse control. Further studies on the pigs’ cognitive capabilities to adjust or coordinate their behaviour to conspecifics are important as they have potential implications for their welfare.