Bennett Matthew R. - Human Footprints: Fossilised Locomotion?

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Watch couples dance or children play and you will see the foot in action; an amazing machine. Just 26 bones sheathed in skin and sinew, with muscles that can propel you forward, backwards, up and down, allowing you to twist, turn, balance and control your speed with precision. Yet despite over a hundred years of research (Morton ) our understanding of the human foot remains rudimentary and knowledge of how our ancient ancestors walked a subject of conjecture and debate.

Within the geological record human and animal tracks occur infrequently; freak occurrences of sedimentary preservation, with each one holding a rare glimpse of locomotive behaviour (Fig. ). The ability of our ancestors to walk efficiently will have influenced their interaction with the landscape: the way they foraged and hunted for food, gathered raw materials to use as tools and their ability to migrate across the globe.

Fossil foot bones of early hominins are rarely found in association with the skeletons of known hominin species and the fossil record is fragmentary. Small bones of the foot scatter easily once released from the soft-tissue that surrounds them and consequently they are poorly preserved in the geological record prior to the advent of burial practices. But in truth fossil foot bones alone rarely give an unambiguous indication of the way our early ancestors walked, since the bones of the foot act through a series of complicated soft tissues which are not preserved. Human tracks provide an alternative source of evidence about our ancestors feet, formed as they walked across soft-ground leaving a record of fossilised locomotion. The critical question is how do tracks record the forces applied to the ground by a track-maker and what can these forces tell us about the way in which they walked? As the foot meets the ground it interacts with the substrate to leave a track which involves the convergence of biomechanics and geology.

There is also an ever growing number of human track sites discovered around the world from more recent times made by Homo sapiens found in such diverse settings as coastal mudflats, caves and imprinted in layers of volcanic ash (Allen ). Here geoarchaeology converges with modern forensic science with both parties having the opportunity to learn from one another.

In light of the above the aims of this volume are therefore varied and we identify four main goals: (1) to draw together in one place, a diverse literature for those interested in human tracks whether they be geologists, archaeologists, palaeoanthropologists or forensic scientists; (2) to provide a review of modern methods of data collection and analysis; (3) to explore the role and influence of substrate on track formation and preservation; and (4) to clearly state what can and cannot be inferred from human tracks. The structure of the book follows these four broad aims, but first we need to clarify some key issues of nomenclature and orientate ourselves with respect to the human foot. We recognise that those reading the book are likely to have different academic backgrounds and have therefore included a glossary located at the end of the book to aid the reader navigate any specialist terms with which they are not familiar.

Fossil footprints whether made by humans or other animals are examples of trace fossils and the technical term for a trace fossil is an ichnofossil. The study of trace fossils is therefore the study of ichnology derived from the Greek ikhnos meaning track or trace. Current convention mainly derived from the study of dinosaur traces is to refer to individual footprints as tracks and a linked sequence of tracks (i.e. footsteps) as a trackway, while the track-maker is the individual who left the tracks (Table ) it is not a methodology that has been widely applied to human tracksites and is not an approach that is favoured here.