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Monday, September 14, 2015

Homo Naledi discovered, thanks to small skinny cavers

We have a new member of the human family tree and I don't know which is more wonderful: the way Homo naledi was found or all the things we'll learn about our own evolution thanks to this discovery. 

Today, let's take a look at the discovery itself, which took place in October, 2013. We'll cover what this means tomorrow.

Lee Berger, a National Geographic Explorer-in-Residence, decided that it had been too long since he last explored. Five years earlier he (along with his then nine year old son) discovered Australopithecus sediba, a two million year old hominid, and had spent the intervening years analyzing that find. In 2013, he decided it was high time he got back in the field.




In Berger's case, the field turned out to be the Rising Star Cave system in South Africa. There, a caver named Steve Tucker inadvertently discovered a chamber full of hominid bones. Unfortunately, that chamber was extremely hard to access. Tucker and his fellow caver Rick Hunter lacked the expertise to safely collect the fossils, and Berger himself couldn't even get to the chamber. Take a look at the graphic below to see why. 
JASON TREAT, NGM STAFF; NGM MAPS
SOURCE: LEE BERGER, WITS

A social media request for small, skinny individuals with scientific credentials, caving experience, and no claustrophobia brought in nearly 60 applicants, out of which Berger selected six women: Marina Elliott, Hannah Morris, Becca Peixotto, Alia Gurtov, Lindsay Eaves and Elen Feuerriegel

Safely removing the fragments without crushing the fragile pieces of bone or getting in each other's way was a delicate task requiring yoga poses and cramping muscles. And that was after they made their way into the chamber.


Nonetheless, the 'underground astronauts' mostly Ph.D. students in anthropology, were all reluctant to leave at the end of their two hour shifts, often doubling or even tripling their time in the chamber.

Working in three person teams, the six women managed to retrieve over 1500 bone fragments, all from the same human ancestor species, now called Homo naledi. Naledi means 'star' in the local language.

Tomorrow: what we've learned from this find.