The evolution of mammalian brain size
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Date
2021
Authors
Smaers, J. B.
Rothman, R. S.
Hudson, D. R.
Balanoff, A. M.
Beatty, B.
Dechmann, D. K. N.
de Vries, D.
Dunn, J. C.
Fleagle, J. G.
Gilbert, C. C.
Journal Title
Journal ISSN
Volume Title
Publisher
American Association for Advancement of Science
Abstract
Relative brain size has long been considered a reflection of cognitive capacities and has played a fundamental role in developing core theories in the life sciences. Yet, the notion that relative brain size validly represents selection on brain size relies on the untested assumptions that brain-body allometry is restrained to a stable scaling relationship across species and that any deviation from this slope is due to selection on brain size. Using the largest fossil and extant dataset yet assembled, we find that shifts in allometric slope underpin major transitions in mammalian evolution and are often primarily characterized by marked changes in body size. Our results reveal that the largest-brained mammals achieved large relative brain sizes by highly divergent paths. These findings prompt a reevaluation of the traditional paradigm of relative brain size and open new opportunities to improve our understanding of the genetic and developmental mechanisms that influence brain size.
Description
Open access article. Creative Commons Attribution NonCommercial license (CC BY-NC) applies
Keywords
Brain size , Body size , Brain-body allometry , Mammalian evolution
Citation
Smaers, J. B., Rothman, R. S., Hudson, D. R., Balanoff, A. M., Beatty, B., Dechmann, D. K. N., de Vries, D., Dunn, J. C., Fleagle, J. G., Gilbert, C. C., Goswami, A., Iwaniuk, A. N., Jungers, W. L., Kerney, M., Ksepka, D. T., Manger, P. R., Mongle, C. S., Rohlf, F. J., Smith,... Soligo, C. (2021). The evolution of mammalian brain size. ScienceAdvances, 7(18), Article eabe2101. https://doi.org/10.1126/sciadv.abe2101