Have you ever taken a walk on a beach, down by the waves, where the rising tide rushes up to wash away any evidence of you ever having been there?
You were, of course, there nonetheless, however your impression was simply not left in a medium conducive to preserving your footprint for seldom more than a few scant minutes. What can your footprints tell you about you, though?
Funnily enough, there is actually a great deal of information contained within your footprints, though perhaps not if they only last a few seconds. You can, for example, tell a person’s stride length, their gait, approximate weight, whether they walk with a limp or some form of impediment from the depth and any drag created by the print. The imprint of the foot its self can tell a lot about the positioning of the bones of your feet, which will allow those who view it to distinguish your print from that of a bear, dog or gorilla (not that many gorillas live on beaches).
Put simply, if you put your foot in the sand, an anthropologist could describe you with some amount of accuracy.
3.5 million years ago, two hominins in Laetoli in Tanzania walked side-by-side across a bed of ash from a nearby erupting volcano. Soon after their stroll, rain immortalised their footprints by mixing with the ash to form a type of concrete. These footprints, left by some anonymous ancestor of humanity, are strikingly similar, if not indistinguishable, from that of you or I.
While no fossilised remains were found at the site, the footprints were found in the same strata (Argon/Argon isotope dating used) as a well known australopithecine from relatively nearby, Australopithecus afarensis. The footprints are yours. They show bipedalism equal to yours, there is advanced hominin looking big toe mark (i.e. not a thumb like gorilla/ape big toe) and moreover, there were flecks of a pink nail polish on the smaller footprints, suggesting that our ancestors were subject to the same vanity affecting modern human females. Yes, that last part was a joke.
Who were these people?
The smaller footprints were either made by a child or a female of the species which exhibited some form of sexual dimorphism (significant difference in body weight and morphology between the sexes). The gait suggested placement of the hips and leg bones much yours, a theory which has been reinforced by the fossilised remains of Lucy and other hominin skeletons found in the area.
Was this a father and his child? Was it a male and his mate?
Australopithecus afarensis had a cranial capacity of around 410cc (humans average 1400cc), so while it would be naïve to suggest that these two australopithecines – these two potential progenitors of humanity – were walking across the African savannah hand in hand into the sunset, it sure is evocative.
Feder, K. L., 2010. The Past in Perspective. 5th ed. USA: Oxford University Press.
Scientific American. 1996. Mary Leakey: Unearthing History. [ONLINE] Available at: http://www.scientificamerican.com/article.cfm?id=mary-leakey-unearthing-hi&page=3. [Accessed 12 August 11].
Scientific American. 1998. Preserving the Laetoli Footprints. [ONLINE] Available at: http://www.sciamdigital.com/index.cfm?fa=Products.ViewIssuePreview&ISSUEID_CHAR=8DB2FB44-6B4B-47AF-B46B-791A911764D&ARTICLEID_CHAR=6EC88BD9-D7E5-4048-AB6D-D5AFCCA929F. [Accessed 12 August 11].
The Smithsonian Institution. 2009. Laetoli Footprint Trails. [ONLINE] Available at: http://humanorigins.si.edu/evidence/behavior/laetoli-footprint-trails. [Accessed 12 August 11].
Jake is the author of ‘Letters to Christian Leaders; Hollow be thy claims’, the book which takes the specific claims that the most prominent Christian Leaders make and directly refutes them using the latest research and evidence, reason, logic, and a dash of snarky humour. Get it here for your sexy kindle. Or if you prefer the authenticity of a book (and are too cheap for a kindle) get the hardcopy here.