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
The first prehistoric chef who looked out at a field of grass in Africa and said, "dinner!" may have helped our ancestors use new resources in new locations.
Roberto Schmidt/AFP/Getty Images