The infertility trap: The fertility costs of group-living in mammalian social evolution

Journal article

Abstract:: Mammal social groups vary considerably in size from single individuals to very large herds. In some taxa, these groups are extremely stable, with at least some individuals being members of the same group throughout their lives; in other taxa, groups are unstable, with membership changing by the day. We argue that this variability in grouping patterns reflects a tradeoff between group size as a solution to environmental demands and the costs created by stress-induced infertility (creating an infertility trap). These costs are so steep that, all else equal, they will limit group size in mammals to ∼15 individuals. A species will only be able to live in larger groups if it evolves strategies that mitigate these costs. We suggest that mammals have opted for one of two solutions. One option (fission-fusion herding) is low cost but high risk; the other (bonded social groups) is risk-averse, but costly in terms of cognitive requirements.

Files:: Dunbar-and-Shultz-2021-The-infertility-trap.pdf

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Language:: English
Keywords:: cognition

fertility

reproductive endocrinology

predation

fission-fusion sociality

coalitions

FFR

primates
Pubs id:: 1211710
Local pid:: pubs:1211710
Deposit date:: 2022-01-06

Copyright holder:: Dunbar and Shultz.
Rights statement:: © 2021 Dunbar and Shultz. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

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