Bonobos have a more human-like second-to-fourth finger length ratio (2D:4D) than chimpanzees: a hypothesized indication of lower prenatal androgens

Matthew h. Mcintyre; Esther Herrmann; Victoria Wobber; Michel Halbwax; Crispin Mohamba; Nick De sousa; Rebeca Atencia; Debby Cox; Brian Hare

doi:10.1016/j.jhevol.2008.12.004

Bonobos have a more human-like second-to-fourth finger length ratio (2D:4D) than chimpanzees: a hypothesized indication of lower prenatal androgens

Matthew h. Mcintyre, Esther Herrmann, Victoria Wobber, Michel Halbwax, Crispin Mohamba, Nick De sousa, Rebeca Atencia, Debby Cox, Brian Hare

Research output: Contribution to journal › Article › peer-review

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.

Original language	English
Pages (from-to)	361-365
Journal	Journal of Human Evolution
Volume	56
Issue number	4
DOIs	https://doi.org/10.1016/j.jhevol.2008.12.004
Publication status	Published - 1 Apr 2009

Keywords

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

Access to Document

10.1016/j.jhevol.2008.12.004

Cite this

@article{822df5f2a8f048d0b46ad9ce51982ec6,

title = "Bonobos have a more human-like second-to-fourth finger length ratio (2D:4D) than chimpanzees: a hypothesized indication of lower prenatal androgens",

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.",

keywords = "digit ratios, 2D:4D, second-to-fourth finger length ratio, prenatal androgens, sex differences, social behavior",

author = "Mcintyre, {Matthew h.} and Esther Herrmann and Victoria Wobber and Michel Halbwax and Crispin Mohamba and {De sousa}, Nick and Rebeca Atencia and Debby Cox and Brian Hare",

year = "2009",

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doi = "10.1016/j.jhevol.2008.12.004",

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T1 - Bonobos have a more human-like second-to-fourth finger length ratio (2D:4D) than chimpanzees: a hypothesized indication of lower prenatal androgens

AU - Mcintyre, Matthew h.

AU - Herrmann, Esther

AU - Wobber, Victoria

AU - Halbwax, Michel

AU - Mohamba, Crispin

AU - De sousa, Nick

AU - Atencia, Rebeca

AU - Cox, Debby

AU - Hare, Brian

PY - 2009/4/1

Y1 - 2009/4/1

N2 - 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.

AB - 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.

KW - digit ratios

KW - 2D:4D

KW - second-to-fourth finger length ratio

KW - prenatal androgens

KW - sex differences

KW - social behavior

U2 - 10.1016/j.jhevol.2008.12.004

DO - 10.1016/j.jhevol.2008.12.004

M3 - Article

SN - 0047-2484

VL - 56

SP - 361

EP - 365

JO - Journal of Human Evolution

JF - Journal of Human Evolution

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