New study: Telling dolphins apart by faces – a new way of identifying dolphins

In a recent study, researchers from Morigenos – Slovenian Marine Mammal Society, an ACCOBAMS Partner, show that individual dolphins can be identified by their faces, “inventing” a novel method of dolphin identification. They presented their findings in a paper published in Marine Mammal Science, the central scientific journal for studies of marine mammals.

Individual identification plays a major role in our understanding of the biology, ecology and behavior in cetaceans. Being able to tell individuals apart can provide invaluable insight into basic biological and scientific questions, but is also highly relevant to science-based conservation. It has long been known that individual dolphins can be identified by natural markings on dorsal fins. But markings on fins can change, and calves are usually not sufficiently marked to allow identification at all. Therefore, additional means of telling dolphins apart can be very useful.

In this study, authors present a novel identification method of using facial information, with wild common bottlenose dolphins (Tursiops truncatus) as a case study. They show that facial features in bottlenose dolphins are long-term and consistent across the left and right sides.

This new method cannot replace the identification based on dorsal fins, but it can complement it, by helping document mark changes over time and reduce false negative or positive errors. Unlike dorsal fins, faces are not subject to the same level of change due to external influences, and may therefore be more reliable over long periods. This new method may also enable calves (which tend to have unmarked fins) to be re-identified after weaning, thus increasing cross-generational knowledge. It may be particularly suited to species that do not carry many markings on dorsal fins, or those that lack dorsal fins altogether.

This study also shows that current identification methods can still be improved. With increasing prevalence of digital photography and computer-aided matching, it may become more viable to use ‘unconventional’ means of identification. The authors encourage other researchers to explore their photographic records for similar discoveries.

The paper can be obtained at