Spontaneous approaches of divers by free-ranging orcas (Orcinus orca): age- and sex-differences in exploratory behaviours and visual laterality

• Published in: Scientific Reports
• Main Authors: Chanvallon, Stéphanie, Blois-Heulin, Catherine, Robert de Latour, Pierre, Lemasson, Alban
• Other Authors: Ethologie animale et humaine (EthoS), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), USEA - Orques Sans Frontières
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: Visual system; Psychology; Behavioural ecology; [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology; [SCCO.NEUR]Cognitive science/Neuroscience; [SDV.NEU.PC]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]/Psychology and behavior; [SDV.NEU.SC]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]/Cognitive Sciences; [SDV]Life Sciences [q-bio]; Orca; Orcinus orca
• Online Access: https://hal-univ-rennes1.archives-ouvertes.fr/hal-01583555; https://hal-univ-rennes1.archives-ouvertes.fr/hal-01583555/document; https://hal-univ-rennes1.archives-ouvertes.fr/hal-01583555/file/Chanvallon_et_al_-_Sci_Rep-2017.pdf; https://doi.org/10.1038/s41598-017-11488-3

International audience Running comparative studies of laterality in mammals is a way to deepen our understanding of the evolution of the brain hemisphere functions. Studies on vision highlighted a possible task-sharing between hemispheres depending on the characteristics of the observers, the nature of the observed stimulus and the context of the observation, a phenomenon that could go beyond the monitoring of conspecifics. Cetaceans are predators that adapted to an aquatic habitat and display a clear crossing of fibers to the side of the brain opposite the eye of origin. Here, we analysed the interactions between humans and cetaceans when free-ranging orcas approach divers. Our study concentrated on the spontaneous exploratory behaviours of divers by orcas depending on their age and sex, and on the possible expression of a visual laterality. The results showed a significant preference for the use of the left eye but exclusively in adult females. Adult males had a more sustained attention than adult females, marked by a higher spatial proximity to divers, slower approaches and longer look durations. Adult females, probably more cautious, explored from the distance and more furtively. Our findings support a possible link between attentional/motivational states and visual laterality in mammals.