Domestic pigs, Sus scrofa, adjust their foraging behaviour to whom they are foraging with

Abstract

Subordinate domestic pigs show behavioural tactics similar to the ones described as tactical deception in primates and corvids when foraging with scrounging dominants for a single monopolizable food source. Here we investigated further whether they can learn deceptive tactics to counter a scrounger by first retrieving the smaller of two hidden food baits, and whether they can discriminate between different types of co-forager. Seven subordinate pigs were tested with co-foragers, and also alone, when foraging for two differently sized food baits hidden in two of 12 buckets in a foraging arena. Unlike their co-foragers, the subordinates already knew where the foods were located; co-foragers differed in whether they were scroungers or not. Subordinates did not respond to scrounging with the predicted deceptive tactic of visiting the small bait first. They did, however, lose their overall preference for retrieving the large bait first and increased their foraging speed compared to when foraging with nonscroungers or on their own. The findings suggest the ability to discriminate between different individual co-foragers in domestic pigs, and increasing foraging speed as a way of responding to exploitation by scrounging dominants in competitive foraging situations with several food patches.