Juvenile pigs use simple geometric 2D shapes but not portrait photographs of conspecifics as visual discriminative stimuli

Several animals living in social groups, such as monkeys, cows and sheep, have been shown to use facial discrimination for social recognition. Whether pigs can discriminate between faces of conspecifics purely based on visual stimuli provided by 2D portrait photographs, has not yet been investigated. Therefore, in this study piglets with a large birth weight […]