Title

Bonobos Have A More Human-Like Second-To-Fourth Finger Length Ratio (2D:4D) Than Chimpanzees: A Hypothesized Indication Of Lower Prenatal Androgens

Keywords

2D:4D; digit ratios; prenatal androgens; second-to-fourth finger length ratio; sex differences; social behavior

Abstract

The ratio of the second-to-fourth finger lengths (2D:4D) has been proposed as an indicator of prenatal sex differentiation. However, 2D:4D has not been studied in the closest living human relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). We report the results from 79 chimpanzees and 39 bonobos of both sexes, including infants, juveniles, and adults. We observed the expected sex difference in 2D:4D, and substantially higher, more human-like, 2D:4D in bonobos than chimpanzees. Previous research indicates that sex differences in 2D:4D result from differences in prenatal sex hormone levels. We hypothesize that the species difference in 2D:4D between bonobos and chimpanzees suggests a possible role for early exposure to sex hormones in the development of behavioral differences between the two species. © 2009 Elsevier Ltd. All rights reserved.

Publication Date

1-1-2009

Publication Title

Journal of Human Evolution

Volume

56

Issue

4

Number of Pages

361-365

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.jhevol.2008.12.004

Socpus ID

64649103686 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/64649103686

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