An inside view of this fossil Pseudodon shell shows that the hole made by Homo erectus is exactly at the spot where the muscle attached to the shell. Poking at that spot would force the shell open.
Henk Caspers/Naturalis Leiden/The Netherlands
A piece of red ochre with a deliberately engraved design is pictured here at Cape Town's Iziko/South African Museum in 2002. The piece was discovered in Blombos Cave near Stilbaai, about 300 kilometers from Cape Town.
Anna Ziemenski/AFP/Getty Images