A team of researchers from different Spanish universities, in fact, headed by javier ruizfrom the Complutense University, and of which he has been a part Juan Luis Arsuaga, co-director of the Atapuerca sites, has just discovered that at least one of the hominids that left their footprints in Laetoli 3.7 million years ago measured 1.70 meters. That is, it was similar in size to ours. The finding has just been published in the journal ‘Ichnos’.
The Laetoli site is famous for the discovery in the 1970s of the skeleton of Lucy, a Australopithecus afarensis who lived 3.2 million years ago, known as ‘the grandmother of humanity’. However, there was more than bones there: there were footprints. These tracks have been the focus of numerous investigations into locomotion, speed, body size, and behavior of animals. A. afarensis who left them The footprints constitute an impressive record of australopithecus walking across a bed of rain-soaked volcanic ash nearly 3.7 million years ago.
In one of the places with hominid footprints, known as ‘site G’, the passage of three individuals walking in the same direction was recorded, with one of them stepping on the footprints left by another larger one.
Until now it has not been possible to know for sure whether these three australopithecines walked apart or together, and if so, how their respective movements were related. Something that Javier Ruiz and his colleagues have now achieved.
The largest of the three was probably a male about 1.70 meters tall, extraordinarily large for its species. The two smallest, measuring 1.40 and 1.20 meters, respectively, must have been a female and a juvenile. Both walked together and closely followed the largest individual.
For their work, the researchers used a high-resolution digital model of the footprints, and on it they were able to calculate the speeds and trajectories of the Laetoli hominins. The fact that the speed of movement was very similar in all three indicates that it is most likely that all three moved together.
The research shows that the detailed calculation of speeds and trajectories from fossil footprints makes it possible to deduce aspects of hominin behavior even millions of years after they left their footprints on the surface. Footprints that are, after all, the ‘fossilized behaviour’ of our remote ancestors.