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 hide caption

itoggle caption Henk Caspers/Naturalis Leiden/The Netherlands

A rendering of Neanderthals cooking and eating. The ancient humans inhabited Europe and western Asia between 230,000 and 29,000 years ago. Mauricio Anton/Science Source hide caption

itoggle caption Mauricio Anton/Science Source

Love your hair. Artists' depictions of a Neanderthal man and woman at the Neanderthal Museum in Mettmann, Germany. Martin Meissner/AP hide caption

itoggle caption Martin Meissner/AP

Research excavations like these in Siberia's Denisova Cave are yielding clues to the mating choices of early hominids. Bence Viola/Nature hide caption

itoggle caption Bence Viola/Nature