Digit ratios predict polygyny in early apes, Ardipithecus, Neanderthals and early modern humans but not in Australopithecus

Nelson, Emma ORCID: 0000-0002-6302-3352, Rolian, Campbell, Cashmore, Lisa and Shultz, Susanne (2011) Digit ratios predict polygyny in early apes, Ardipithecus, Neanderthals and early modern humans but not in Australopithecus. PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, 278 (1711). pp. 1556-1563.

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Official URL: http://dx.doi.org/10.1098/rspb.2010.1740

Abstract

Social behaviour of fossil hominoid species is notoriously difficult to predict owing to difficulties in estimating body size dimorphism from fragmentary remains and, in hominins, low canine size dimorphism. Recent studies have shown that the second-to-fourth digit ratio (2D : 4D), a putative biomarker for prenatal androgen effects (PAEs), covaries with intra-sexual competition and social systems across haplorrhines; non-pair-bonded polygynous taxa have significantly lower 2D : 4D ratios (high PAE) than pair-bonded monogamous species. Here, we use proximal phalanx ratios of extant and fossil specimens to reconstruct the social systems of extinct hominoids. Pierolapithecus catalaunicus, Hispanopithecus laietanus and Ardipithecus ramidus have ratios consistent with polygynous extant species, whereas the ratio of Australopithecus afarensis is consistent with monogamous extant species. The early anatomically modern human Qafzeh 9 and Neanderthals have lower digit ratios than most contemporary human populations, indicating increased androgenization and possibly higher incidence of polygyny. Although speculative owing to small sample sizes, these results suggest that digit ratios represent a supplementary approach for elucidating the social systems of fossil hominins.

Item Type:	Article
Uncontrolled Keywords:	pair-bonded, polygyny, prenatal androgens, hominin, social system, second-to-fourth digit length ratio
Depositing User:	Symplectic Admin
Date Deposited:	11 Jan 2016 11:42
Last Modified:	18 Oct 2023 09:55
DOI:	10.1098/rspb.2010.1740
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/2045680