Perhaps the most famous footsteps on this planet (thereby excluding Armstrong’s on the moon) were set in a dusting of volcanic ash in Laetoli Tanzania by human ancestors (or close relatives of human ancestors) 3.7 million years ago. There are plans to build a museum around them. When first discovered in 1976, the prints were interpreted as belonging to three individuals, with one (perhaps a child) deliberately stepping in the prints of another. (Why? Playfulness? Was the undisturbed ash hot?) Recently, some scientists have argued that there were four individuals – the evidence consists of what may be three discrete big toe marks in the overstepped prints, though the case for this is unsettled. No one knows for sure to what species the amblers belonged, but the prints show a posture and a gait identical to those of modern humans. Researchers have duplicated the tracks simply by walking barefoot.
I’ve never seen Laetoli in person (the prints currently are buried anyway in order to preserve them), but I have met Lucy, the 3.2 million-year-old Australopithecus afarensis who must have been very much like the print-makers, if not actually one of their species. There is disagreement among anthropologists over whether Lucy was a hominin (direct human ancestor) or a non-ancestral hominid (a larger group including hominins). Either way, she is family; if she is not a great great grandmother, she is something like a great aunt. I met her twice, actually: once during a visit her fossil made to the Museum of Natural History and once again a few years ago at the Discovery Times Square Exhibition in NYC.
Lucy’s celebrity has been upstaged lately by Ardi. Ardi is the nickname of a 4.4 million-year-old female Ardipithecus ramidus described in Science magazine in 2009. However, Ardi is 110 fragments that don’t look like much of anything, no matter how you arrange them. Lucy is complete enough to be satisfyingly recognizable. (Yeah, I know: just like a man to prefer the younger woman.)
Viewing Lucy evoked a curious sensation that was not quite nostalgia, but something like it. It was something akin to handling a quilt sewn by a family member who died over a century ago.
What is our legacy from Lucy? How much of her nature remains our own? It’s hard to say, but perhaps we have more in common with her than we commonly acknowledge. It’s a long way from Laetoli, but, for well or ill, we all still walk in Lucy’s footsteps.