Dear MARMAM community, My co-authors and I are pleased to share our new paper, now published open access in Animal Behaviour: Veys, M.-L., Jourdain, E., O'Callaghan, S., Berthier, J., & Freitas, C. (2026). Female-centred decision making and social interactions in killer whales revealed by drone-based observations. Animal Behaviour, 241, 123732. https://doi.org/10.1016/j.anbehav.2026.123732 Using drone footage collected in Hardangerfjord, Norway, between February and April 2025, we examined who initiates collective deep dives in killer whale groups and how social interactions are distributed among age-sex classes. Across 45 collective deep dives, adult females initiated 82% of dives, significantly more than adult males or juveniles, and calves never did. This points to unshared decision making linked to age-sex class. Initiators were often, but not necessarily, at the front of the group. The distribution of dive lags was right-skewed with a mean of 14.6 s, indicating rapid responses by group members to a single initiator, and neither group size nor behavioural context (travelling versus resting) significantly affected dive lags or interindividual dive intervals. Synchronized surfacing and physical contact were most frequent between adult females and calves, and were rare or absent during foraging. The dataset is small (16 individuals from three family groups), so we consider the results exploratory, but they illustrate how drone-based observations can reveal fine-scale social behaviour in a noninvasive way. To our knowledge, this is one of the first studies of leadership during group dives in killer whales outside the North Pacific. Please feel free to contact me with any questions at [email protected] Best wishes, Marie-Laure Veys |
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