In this study, the presence of potential self-awareness traits was tested for in single and groups of wild Adelie penguins, on a remote island in Antarctica, by examining their postural and gestural responses, and reactions to their images in mirrors, during four innovative experimental paradigms: group-behaviour test, modified mirror test, hidden-head test, and the coloured-bib test. This investigation represents a pioneering attempt in conducting a set of cognitive experiments on free-ranging individuals of a nonhuman species in their natural environment, without any prior familiarisation, conditioning, or acclimatisation to the observation conditions. More academically, we argue, firstly, that the self-awareness trait, which we report here, may have evolved in the course of the cooperative behaviour displayed by individual penguins towards conspecific individuals in their colonies. Secondly, we believe that self-awareness could lie within an aggregated complex of social cognitive abilities, which may have evolved as an essential social requirement for the intensely cooperative lifestyle evolved by these penguins, and possibly by other social species, inhabiting difficult environmental conditions.
