Brief communication

Hair density and body mass in mammals and the evolution of human hairlessness

Bibliographic Data

ID8312334
AuthorsAaron A Sandel (0000-0003-3060-5310, Department of Anthropology University of Michigan Ann Arbor MI 48109, corresponding author)
Year2013
Volume152
Issue1
Pages145-150
Publication date2013-09-01
Peer ReviewedYes
Open AccessYes
TypeARTICLE
VenueAmerican Journal of Physical Anthropology (JOURNAL)
Journal identifiersISSN: 0002-9483 • E-ISSN: 1096-8644
PublisherWiley (PUBLISHER • GB)
DOI10.1002/ajpa.22333
PMID23900811
OpenAlexW1799093875
LanguageEN
Citations received5
References cited37

Humans are unusual among mammals in appearing hairless. Several hypotheses propose explanations for this phenotype, but few data are available to test these hypotheses. To elucidate the evolutionary history of human “hairlessness,” a comparative approach is needed. One previous study on primate hair density concluded that great apes have systematically less dense hair than smaller primates. While there is a negative correlation between body size and hair density, it remains unclear whether great apes have less dense hair than is expected for their body size. To revisit the scaling relationship between hair density and body size in mammals, I compiled data from the literature on 23 primates and 29 nonprimate mammals and conducted Phylogenetic Generalized Least Squares regressions. Among anthropoids, there is a significant negative correlation between hair density and body mass. Chimpanzees display the largest residuals, exhibiting less dense hair than is expected for their body size. There is a negative correlation between hair density and body mass among the broader mammalian sample, although the functional significance of this scaling relationship remains to be tested. Results indicate that all primates, and chimpanzees in particular, are relatively hairless compared to other mammals. This suggests that there may have been selective pressures acting on the ancestor of humans and chimpanzees that led to an initial reduction in hair density. To further understand the evolution of human hairlessness, a systematic study of hair density and physiology in a wide range of species is necessary. Am J Phys Anthropol 152:145–150, 2013. © 2013 Wiley Periodicals, Inc

Biological evolution · Biology · Body hair · Evolutionary biology · Hominidae · Primate · Range (aeronautics) · Zoology · Anatomy · Animal Vocal Communication and Behavior · Bat Biology and Ecology Studies · Ecology · Genetics · Primate Behavior and Ecology

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