Face to face: human recognition of Asian elephant facial features.

Especially in species with complex social systems, the relatedness between individuals is important information. Visual phenotypic cues present one way to identify closely related conspecifics. Humans are capable of recognizing such visual cues in the faces of their own as well as several primate species, but to which degree this applies to non-primate species is largely unexplored. Here we demonstrate the capability of 110 test persons to recognize faces of 47 male Asian elephants based on 186 photographs. The human examiners were not only able to recognize an individual based on its face after several years, but also to identify, at decreasing accuracy, full brother pairs and paternal kinship. People regularly working with elephants were more successful than laypersons. However, even laypersons recognized 73.3% of the same individuals. The identification of individual elephants by a look at their faces presents a simple approach which can be a valuable tool for in situ research. [ABSTRACT FROM AUTHOR]