Dr Jeff Meldrum is Professor of Anatomy and Anthropology at Idaho University. He has extensively studied the adaptations of the feet of African primates with their implications in the evolution of human bipedalism, and was the senior editor of the scientific book, From Biped to Strider: the emergence of modern human walking, running, and resource transport. In short, he is an expert on human, monkey and ape feet and gaits, and the sort of footprints they produce. But then, in 1996 in the Blue Mountains of Washington State, he was introduced to a set of footprints which blew his mind.