Laetoli Footprints Preserve Earliest Direct Evidence of Human-Like Bipedal Biomechanics

David A Raichlen, Adam D. Gordon, William E H Harcourt-Smith, Adam D. Foster, Wm Randall Haas

Research output: Contribution to journalArticle

85 Citations (Scopus)

Abstract

Background: Debates over the evolution of hominin bipedalism, a defining human characteristic, revolve around whether early bipeds walked more like humans, with energetically efficient extended hind limbs, or more like apes with flexed hind limbs. The 3.6 million year old hominin footprints at Laetoli, Tanzania represent the earliest direct evidence of hominin bipedalism. Determining the kinematics of Laetoli hominins will allow us to understand whether selection acted to decrease energy costs of bipedalism by 3.6 Ma. Methodology/Principal Findings: Using an experimental design, we show that the Laetoli hominins walked with weight transfer most similar to the economical extended limb bipedalism of humans. Humans walked through a sand trackway using both extended limb bipedalism, and more flexed limb bipedalism. Footprint morphology from extended limb trials matches weight distribution patterns found in the Laetoli footprints. Conclusions: These results provide us with the earliest direct evidence of kinematically human-like bipedalism currently known, and show that extended limb bipedalism evolved long before the appearance of the genus Homo. Since extendedlimb bipedalism is more energetically economical than ape-like bipedalism, energy expenditure was likely an important selection pressure on hominin bipeds by 3.6 Ma.

Original languageEnglish (US)
Article numbere9769
JournalPLoS One
Volume5
Issue number3
DOIs
StatePublished - 2010

Fingerprint

Biomechanics
Hominidae
limbs (animal)
Biomechanical Phenomena
Design of experiments
preserves
Kinematics
Sand
Extremities
Costs
Pongidae
Homo
energy costs
Energy Metabolism
biomechanics
Weights and Measures
kinematics
Tanzania
energy expenditure
experimental design

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Laetoli Footprints Preserve Earliest Direct Evidence of Human-Like Bipedal Biomechanics. / Raichlen, David A; Gordon, Adam D.; Harcourt-Smith, William E H; Foster, Adam D.; Haas, Wm Randall.

In: PLoS One, Vol. 5, No. 3, e9769, 2010.

Research output: Contribution to journalArticle

Raichlen, David A ; Gordon, Adam D. ; Harcourt-Smith, William E H ; Foster, Adam D. ; Haas, Wm Randall. / Laetoli Footprints Preserve Earliest Direct Evidence of Human-Like Bipedal Biomechanics. In: PLoS One. 2010 ; Vol. 5, No. 3.
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