Early Human Footprints Discovered in Tanzania Suggest Gorilla-Style Mating Patterns

Lucy fossil
The 3.2 million-year-old fossilized remains of "Lucy", the most complete example of the hominin Australopithecus afarensis, displayed at the Houston Museum of Natural Science, August 28, 2007 in Texas. Scientists have discovered footprints believed to belong to members of Lucy's species in Tanzania. Dave Einsel/Getty

Scientists have discovered another set of ancient footprints at an archaeological site in Tanzania, which is already home to the earliest footprints belonging to human ancestors.

Researchers unearthed footprints thought to belong to Australopithecus afarensis—one of the earliest hominin species—at a site in Laetoli, Tanzania, in 1976. The footprints were estimated to be 3.66 million years old and are therefore the oldest record of bipedal motion, or walking on two legs.

In a study published in the journal eLife on Thursday, scientists from a Tanzanian university and Italian universities said they had discovered fresh footprints from a similar era, which they think may have been made by a male walking with several smaller females.

The researchers discovered 13 prints belonging to a larger individual measuring around 165cm, who they believe may have been a larger male of the species. A single print belonging to another smaller australopith has also been found.

When viewed in combination with the 1976 discovery—in which three sets of footprints were discovered—the new find suggests that ancient hominins may have lived in social groups similar to gorillas, where a single dominant male mates and is accompanied by several females and their offspring.

A researcher at the University of Dar es Salaam in Tanzania, Fidelis Masao, made the discovery in 2015 when carrying out preliminary investigations into the viability of building a museum close to the site of the 1976 footprints, according to New Scientist. The tracks are thought to have been made when the ancient hominins walked across wet volcanic ash.

The most famous fossil to be discovered from the Australopithecus afarensis species is a 3.2 million year-old partial skeleton named Lucy, a female hominin discovered in Ethiopia in 1974.