Walk Like A Modern Human: 1.5 Million-Year-Old Footprints Found In Ileret, Kenya

Fossilized footprints were found between two sedimentary layers in Ileret (Rutgers' Koobi Fora Field School), Kenya that dates back about 1.5 million-years-ago. These footprints show that its owner was walking upright, bipedally and the foot already had the anatomy like those of modern humans: relatively adducted hallux (big toe), medial longitudinal arch and medial weight transfer before push-off. The size of the footprints corresponds to the stature and body mass of Homo ergaster, an earlier version of Homo erectus (Bennett et al., 2009).

Cover of Science, 27 February 2009. Optical laser scan of early hominin footprints at Ileret, Kenya, color-rendered to illustrate depth; reds indicate areas of high elevation, blues lower elevation. The footprints are 1.5 million years old and were probably made by Homo ergaster/erectus. Two right footprints and a partial left are visible along with a range of animal prints. Image processing in Rapidform^TM: Matthew Bennett/ Bournemouth University.

These footprints are distinct from the "famous" Laetoli footprints, discovered by Mary Leakey in 1976 at Laetoli, Tanzania which dates to about 3.5 million-years-ago. The Laetoli footprints belong to Australopithecus afarensis and at least two individuals were present, walking side by side.

Laetoli footprints. Photo from www.pbs.com

The Ileret footprints are different and similar to the Laetoli footprints in many ways. Laetoli footprints are more ape-like, Ileret footprints are more human-like. Both, however, do not have an opposable toe like those of chimpanzees. Both footprints indicate that its owner was walking bipedally or has a bipedal gait.

Comparison between a chimpanzee footprint and Australopithecus afarensis (Laetoli) footprint. Photo of chimpanzee footprint from www.elucy.org and photo of Laetoli footprint from www.columbia.edu




Comparison between Homo ergaster (Ileret footprint) and modern human. Photo of Ileret footprint by Matthew Bennett from www.nationalgeographic.com

Read more on "Prints Are Evidence of Modern Foot in Prehumans" by John Noble Wilford.
Rutgers' Press Release: 1.5 Million-Year-Old Fossil Humans Walked on Modern Feet.

Citation:
Bennett MR. Harris JWK. Richmond BG. Braun DR. Mbua E. Kiura P. Olago D. Kibunjia M. Omuombo C. Behrensmeyer AK. Huddart D. Gonzalez S. 2009. Early Hominin Foot Morphology Based on 1.5-Million-Year-Old Footprints from Ileret, Kenya. Science 323 (5918): 1197 - 1201. [DOI: 10.1126/science.1168132]