What is shaping the brain? A perspective on brain size evolution in carnivorans / Margot Michaud

What  is  shaping  the  brain?  A  perspective  on  brain  size  evolution  in carnivorans / Margot Michaud, in colloque "1st Virtual Conference for Women Archaeologists and Paleontologists. Nouveaux apports à l’étude des populations et environnements passés" organisé par le laboratoire Travaux et Recherches Archéologiques sur les Cultures, les Espaces et les Sociétés (TRACES) de l’Université Toulouse Jean Jaurès et le laboratoire Paléontologie Évolution Paléoécosystèmes (PALEVOPRIM) de l'Université de Poitiers, sous la responsabilité scientifique de Julie Bachellerie, Ana Belén Galán López (Traces), Émilie Berlioz et Margot Louail (Palevoprim). Université Toulouse Jean Jaurès, 8-9 mars 2021. Session 1 : Morphological variability, taxonomy and adaptations.

Understanding the selective pressures that have influenced brain evolution is among the greatest challenge in evolutionary biology. Encephalization, to be understood as a larger brain size than predicted for a given body size, is presumed to confer selective advantages due to enhanced cognition and broader behavioural flexibility. However, decades of research on brain evolution have produced conflicting results. Which selective pressures favour larger brains and whether they act in the same way in differenttaxonomical groups remains poorly understood. In this study, we propose to investigate the effect of ecological adaptations, geographic and environmental factors, social complexity, and life-traits features on evolution of brain size in carnivoran species(wolfs, panthers, bears and relatives), using a broad-scale dataset of 174 species. Our results highlighted a complex pattern of brain evolution within this group with differences in both tempo and disparity between families. Moreover, our analyses suggested a strong influence of environmental and ecological factors on encephalization, with the average size of the geographic range being negatively correlated with encephalization in terrestrial carnivorans. In contrast, the relative brain size appears to bepositively influenced by the average home range size. Finally, we founded no evidence in favour of the “Social Brain Hypothesis” often proposed to explain the increase of encephalisation in relation to the complexity of social environment. These results suggest that different selective forces might drive evolution of brain size in carnivoran species and will contribute to a more comprehensive understanding of how the vertebrate brain evolved.