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Mechanical analysis of infant carrying in hominoids

In all higher nonhuman primates, species survival depends upon safe carrying of infants clinging to body hair of adults. In this work, measurements of mechanical properties of ape hair (gibbon, orangutan, and gorilla) are presented, focusing on constraints for safe infant carrying. Results of hair t...

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Autor principal: Amaral, Lia Q.
Formato: Texto
Lenguaje:English
Publicado: Springer-Verlag 2007
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2270361/
https://www.ncbi.nlm.nih.gov/pubmed/18030438
http://dx.doi.org/10.1007/s00114-007-0325-0
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author Amaral, Lia Q.
author_facet Amaral, Lia Q.
author_sort Amaral, Lia Q.
collection PubMed
description In all higher nonhuman primates, species survival depends upon safe carrying of infants clinging to body hair of adults. In this work, measurements of mechanical properties of ape hair (gibbon, orangutan, and gorilla) are presented, focusing on constraints for safe infant carrying. Results of hair tensile properties are shown to be species-dependent. Analysis of the mechanics of the mounting position, typical of heavier infant carrying among African apes, shows that both clinging and friction are necessary to carry heavy infants. As a consequence, a required relationship between infant weight, hair–hair friction coefficient, and body angle exists. The hair–hair friction coefficient is measured using natural ape skin samples, and dependence on load and humidity is analyzed. Numerical evaluation of the equilibrium constraint is in agreement with the knuckle-walking quadruped position of African apes. Bipedality is clearly incompatible with the usual clinging and mounting pattern of infant carrying, requiring a revision of models of hominization in relation to the divergence between apes and hominins. These results suggest that safe carrying of heavy infants justify the emergence of biped form of locomotion. Ways to test this possibility are foreseen here.
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spelling pubmed-22703612008-03-21 Mechanical analysis of infant carrying in hominoids Amaral, Lia Q. Naturwissenschaften Original Paper In all higher nonhuman primates, species survival depends upon safe carrying of infants clinging to body hair of adults. In this work, measurements of mechanical properties of ape hair (gibbon, orangutan, and gorilla) are presented, focusing on constraints for safe infant carrying. Results of hair tensile properties are shown to be species-dependent. Analysis of the mechanics of the mounting position, typical of heavier infant carrying among African apes, shows that both clinging and friction are necessary to carry heavy infants. As a consequence, a required relationship between infant weight, hair–hair friction coefficient, and body angle exists. The hair–hair friction coefficient is measured using natural ape skin samples, and dependence on load and humidity is analyzed. Numerical evaluation of the equilibrium constraint is in agreement with the knuckle-walking quadruped position of African apes. Bipedality is clearly incompatible with the usual clinging and mounting pattern of infant carrying, requiring a revision of models of hominization in relation to the divergence between apes and hominins. These results suggest that safe carrying of heavy infants justify the emergence of biped form of locomotion. Ways to test this possibility are foreseen here. Springer-Verlag 2007-11-21 2008-04 /pmc/articles/PMC2270361/ /pubmed/18030438 http://dx.doi.org/10.1007/s00114-007-0325-0 Text en © Springer-Verlag 2007
spellingShingle Original Paper
Amaral, Lia Q.
Mechanical analysis of infant carrying in hominoids
title Mechanical analysis of infant carrying in hominoids
title_full Mechanical analysis of infant carrying in hominoids
title_fullStr Mechanical analysis of infant carrying in hominoids
title_full_unstemmed Mechanical analysis of infant carrying in hominoids
title_short Mechanical analysis of infant carrying in hominoids
title_sort mechanical analysis of infant carrying in hominoids
topic Original Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2270361/
https://www.ncbi.nlm.nih.gov/pubmed/18030438
http://dx.doi.org/10.1007/s00114-007-0325-0
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