The next steps of our project will examine how some of the more intricate details of locomotion and foot anatomy – for example joint motions and aspects of the foot’s arches – are preserved in footprints across a wider range of sedimentary conditions. With reliable methods for predicting details of body form and function from footprints, we can better understand how exactly Australopithecus and Homo ‘accomplished’ being bipedal despite their very different anatomies. Comparisons of the Laetoli and Ileret fossil footprints will then help to inform us of how function may have driven changes in body form, or vice versa.

Exactly! Fossil footprints must accumulate and be preserved over the course of hours to days, otherwise they will not fossilize. This sets them apart from typical fossil assemblages, where bones accumulate over thousands of years and sites are thus subject to substantial time-averaging.

So with these footprints we can start to get a direct picture of how groups of early humans inhabiting the same landscape interacted with each other, and with the environment around them. We can begin to ask new and exciting questions about early human social behavior, and also address issues of time-averaging in reconstructing the environments in which those early humans lived.

Thank you! The data I presented here come from about 50 adults, 25 men and 25 women. I have yet to find significant distinctions in their foot anatomy or locomotion (other than women being smaller on average) but we do continue to consider, in all of our analyses, sex as a potential source of variation. It will be very exciting if we do find that we can eventually distinguish the footprints of men and women!

Thanks! Our preliminary predictions do fit within the range of what we would expect given the known fossil skeletal evidence from Australopithecus and early Homo. We are lucky in that we are able to derive those predictions from ‘more complete’ pieces of fossil hominin anatomy, with an impression of the total foot rather than just a piece of one bone from the foot, for example.

Thank you! I am very interested in studying how measures of gait performance (e.g., elastic energy return, gait efficiency) might be interpreted from footprints. If we can find ways to interpret those measures from fossil footprints, we can gain some really unique insights into how and why the Australopithecus to Homo transition may have occurred. It would certainly require different and more complicated experimental approaches and analytical techniques though!

Thanks, Michael! Given the encouraging results from our experimental work, we’re hopeful that we’ll be able to provide new and exciting insight to inform hypotheses regarding the anatomy and locomotion of hominins from two very different points in our evolution.

Thanks, Ashley! We acknowledge that we aren’t able to perfectly control every variable but we are trying our best!

Thanks, Gillian! Unfortunately, I am still in the data processing phase regarding the fossil trackways. But with results that are encouraging so far regarding our abilities to infer aspects of anatomy and locomotion from footprints, hopefully we’ll be able to say something very soon about those fossils! We’re specifically hoping to test ideas about how Australopithecus and Homo may have used different forms of bipedalism, and how their overall anatomy may have led to, or resulted from, selection for that behavior.