An unusual encounter with a group of orcas near Iceland led researchers to discover a new and complex behaviour – the orcas had taken in baby pilot whales, and not necessarily to eat them. Scientists watched two encounters between the orcas and several weeks-old baby pilot whales in 2022 and 2023. They examined an earlier case in 2021 to come up with three possible reasons for the unusual behaviour. Firstly, it could have been predatory behaviour, but the researchers noted that the groups of orcas in question largely eat fish only. Another reason was for play, or hunting training. But the third possible reason could be that the orcas were caring for the calves and had potentially adopted the pilot whales, ruling out aggression-based behaviours and infanticide.
They do consider how the pilot whale calves came to be with the orcas in the first place and given that each event was only observed once and the outcome and context are unknown, the authors suggest that it is “difficult at this point to conclude on a single, definitive interpretation of the proximate or ultimate causes of these interactions and it is possible that they have multiple drivers”.
Interestingly, the same behaviour was also seen in the west of Iceland in 2021.
The full study can be read here
