'Small spelunkers required': the ad that led to the discovery of Homo naledi

The skeletons found in a South African cave were retrieved by six scientists with a hard-to-find combination of skills

The advertisement on social media called for "tiny and small specialised cavers and spelunkers with excellent archaeological, palaeontological and excavation skills". And there was a catch: they would work for no pay.

"Why wouldn't you apply, with an advert like that?" recalled successful applicant Elen Feuerriegel, speaking at the Cradle of Humankind world heritage site in South Africa after scientists claimed the discovery of a new human ancestor. "How could you not? It was the thrill of discovery."