Anglia Ruskin Research Online (ARRO)
Browse
Mearing_et_al_2022.pdf (2.13 MB)

The evolutionary drivers of primate scleral coloration.

Download (2.13 MB)
journal contribution
posted on 2023-07-26, 15:59 authored by Alex S. Mearing, Judith M. Burkart, Jacob Dunn, Sally E Street, Kathelijine Koops
The drivers of divergent scleral morphologies in primates are currently unclear, though white sclerae are often assumed to underlie human hyper-cooperative behaviours. Humans are unusual in possessing depigmented sclerae whereas many other extant primates, including the closely-related chimpanzee, possess dark scleral pigment. Here, we use phylogenetic generalized least squares (PGLS) analyses with previously generated species-level scores of proactive prosociality, social tolerance (both n = 15 primate species), and conspecific lethal aggression (n = 108 primate species) to provide the first quantitative, comparative test of three existing hypotheses. The ‘self-domestication’ and ‘cooperative eye’ explanations predict white sclerae to be associated with cooperative, rather than competitive, environments. The ‘gaze camouflage’ hypothesis predicts that dark scleral pigment functions as gaze direction camouflage in competitive social environments. Notably, the experimental evidence that non-human primates draw social information from conspecific eye movements is unclear, with the latter two hypotheses having recently been challenged. Here, we show that white sclerae in primates are associated with increased cooperative behaviours whereas dark sclerae are associated with reduced cooperative behaviours and increased conspecific lethal violence. These results are consistent with all three hypotheses of scleral evolution, suggesting that primate scleral morphologies evolve in relation to variation in social environment.

History

Refereed

  • Yes

Volume

12

Page range

14119

Publication title

Scientific Reports

ISSN

2045-2322

Publisher

Nature Research

File version

  • Published version

Language

  • eng

Legacy posted date

2022-09-16

Legacy creation date

2022-09-16

Legacy Faculty/School/Department

Faculty of Science & Engineering

Usage metrics

    ARU Outputs

    Categories

    No categories selected

    Licence

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC