This was such a fun and rewarding team effort with
@annaselbmann.bsky.social,
Heleen Middel,
@jnschulze.bsky.social,
Giulia Bellon and @fipsamarra.bsky.social!

Funded by Rannís - The Icelandic Center for Research and
@earthwatch-org.bsky.social — thank you for supporting this work!

In our new scientific note published in Ecology & Evolution we explore these rare and puzzling encounters - adding a new layer to what we know about the social lives of killer whales.

The calves stayed close, surfacing in echelon position, but also swimming away from the killer whales, and even being lifted out of the water. Were these interactions playful? Practice for hunting? Or caregiving gone cross-species?

Thank you 🩷

This project was made possible by the long-term data collection efforts of the icelandic-orcas.com and the norwegianorcasurvey.no, and the collaborative efforts of the University of Iceland, University of Oslo, ETH Zurich and the Greenland Institute of Natural Resources.

Therefore, to maintain connectivity and genetic health, the conservation of dietary variation and of the small vulnerable matrilines in North Atlantic killer whales should be prioritised and coordinated across national borders.

However, gene flow has been restricted in recent generations coinciding with the collapse of herring stocks and the cessation of seasonal connectivity between Icelandic and Norwegian herring stocks. "Mixed-diet” Icelandic whales appear to have maintained some gene flow with Norwegian killer whales.

We find maternal lineages are strongly associated with particular geographic regions, and therefore also herring stocks. We therefore propose that male-mediated gene flow connects matrilineal demes.

This contrasts with well-studied Pacific killer whales, which show genetic structuring associated with diet and geography.

Our findings reveal a connected metapopulation spanning Greenland to Norway, and which includes whales with different dietary preferences (fish diet vs. mixed fish/seal diet) still interbreed. …