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Hand and foot pressures in the aye-aye (Daubentonia madagascariensis) reveal novel biomechanical trade-offs required for walking on gracile digits

Kivell, Tracy L., Schmitt, Daniel, Wunderlich, Roshna E (2010) Hand and foot pressures in the aye-aye (Daubentonia madagascariensis) reveal novel biomechanical trade-offs required for walking on gracile digits. The Journal of Experimental Biology, 213 . pp. 1549-1557. ISSN 0022-0949. E-ISSN 1477-9145. (doi:10.1242/jeb.040014) (KAR id:43704)


Arboreal animals with prehensile hands must balance the complex demands of bone strength, grasping and manipulation. An informative example of this problem is that of the aye-aye (Daubentonia madagascariensis), a rare lemuriform primate that is unusual in having exceptionally long, gracile fingers specialized for foraging. In addition, they are among the largest primates to engage in head-first descent on arboreal supports, a posture that should increase loads on their gracile digits. We test the hypothesis that aye-ayes will reduce pressure on their digits during locomotion by curling their fingers off the substrate. This hypothesis was tested using simultaneous videographic and pressure analysis of the hand, foot and digits for five adult aye-ayes during horizontal locomotion and during ascent and descent on a 30 degrees instrumented runway. Aye-ayes consistently curled their fingers during locomotion on all slopes. When the digits were in contact with the substrate, pressures were negligible and significantly less than those experienced by the palm or pedal digits. In addition, aye-ayes lifted their hands vertically off the substrate instead of 'toeing-off' and descended head-first at significantly slower speeds than on other slopes. Pressure on the hand increased during head-first descent relative to horizontal locomotion but not as much as the pressure increased on the foot during ascent. This distribution of pressure suggests that aye-ayes shift their weight posteriorly during head-first descent to reduce loads on their gracile fingers. This research demonstrates several novel biomechanical trade-offs to deal with complex functional demands on the mammalian skeleton.

Item Type: Article
DOI/Identification number: 10.1242/jeb.040014
Uncontrolled keywords: hand posture ; fingers ; foot ; toes ; slope
Subjects: Q Science
Q Science > Q Science (General)
Q Science > QL Zoology
Q Science > QM Human anatomy
Divisions: Divisions > Division of Human and Social Sciences > School of Anthropology and Conservation
Depositing User: Tracy Kivell
Date Deposited: 31 Oct 2014 08:41 UTC
Last Modified: 16 Nov 2021 10:17 UTC
Resource URI: (The current URI for this page, for reference purposes)

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