Researchers unearthed the tracks by accident when they began to
excavate test pits that had been called for as part of an assessment
of the impact of building a proposed museum on the site in Tanzania.
The markings reveal that the ancient human relatives walked side by
side for at least 30 metres. The footprints were laid down in a layer
of ash that was subsequently buried, but which when moistened retained
the tracks like clay.
A first analysis of the footprints suggests that they were made when a
male, three females and a child passed through what is now Laetoli in
the African country. The individuals almost certainly belong to a
species of hairy bipedal ape called Australopithecus afarensis which
is known to have lived in the region.
The layer of ash that preserved the tracks has been dated to 3.66m
years old, the same age as a similar sequence of hominin, or human
ancestor, footprints found nearby by famed palaeontologist Mary Leakey
in the 1970s.
“These footprints enrich our knowledge about the most ancient hominin
footprints in the world,” Cherin told the Guardian. “But they tell us
something about the makers too, in this case that we think there were
significant differences between the males and females. This is the
most striking thing.”
“A tentative conclusion is that the group consisted of one male, two
or three females, and one or two juveniles, which leads us to believe
that the male – and therefore other males in the species – had more
than one female mate,” Cherin added. Details of the tracks are
published in the journal, eLife.