Comparative analysis of encephalization in mammals reveals relaxed constraints on anthropoid primate and cetacean brain scaling

2012/03/21 by Amy M. Boddy, Michael R. McGowen, Chet C. Sherwood +3 · 5 citations
Psychology · Earth and Planetary Sciences · Environmental Science · #Primate Behavior and Ecology #Evolution and Paleontology Studies #Marine animal studies overview

paper · pdf · doi:10.1111/j.1420-9101.2012.02491.x

openalex publication_date 2012/03/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01

Abstract

There is a well-established allometric relationship between brain and body mass in mammals. Deviation of relatively increased brain size from this pattern appears to coincide with enhanced cognitive abilities. To examine whether there is a phylogenetic structure to such episodes of changes in encephalization across mammals, we used phylogenetic techniques to analyse brain mass, body mass and encephalization quotient (EQ) among 630 extant mammalian species. Among all mammals, anthropoid primates and odontocete cetaceans have significantly greater variance in EQ, suggesting that evolutionary constraints that result in a strict correlation between brain and body mass have independently become relaxed. Moreover, ancestral state reconstructions of absolute brain mass, body mass and EQ revealed patterns of increase and decrease in EQ within anthropoid primates and cetaceans. We propose both neutral drift and selective factors may have played a role in the evolution of brain-body allometry.

Citations

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Cited by

• Primate brain size is predicted by diet but not sociality
• Brain Mass and Encephalization Quotients in the Domestic Industrial Pig (Sus scrofa)
• Multivariate Meta-Analysis of Brain-Mass Correlations in Eutherian Mammals
• The pattern of brain-size change in the early evolution of cetaceans
• Encephalization quotient [wikipedia]

Related

• The pattern of brain-size change in the early evolution of cetaceans
• Multivariate Meta-Analysis of Brain-Mass Correlations in Eutherian Mammals
• The evolution of mammalian brain size
• Hominin brain size increase has emerged from within-species encephalization
• The Evolution of Brain and Body Size in Genus Homo