Homo sapiens is genetically very similar to other African apes, yet differs greatly in morphology, physiology and behavior. Not only do we humans walk upright and speak, but we are also characterized by having an exceptional stamina as shown by our aptitude for endurance running, long-distance swimming and breath-hold diving underwater —unlike any other primate. Stamina (or aerobic endurance) has apparently helped humans to spread globally and thrive from seacoasts to high altitudes and from deserts to the poles —while other apes are mostly confined to tropical forests. This global dispersal and colonization of different environments started with our probable ancestor Homo erectus, about 2 million years ago. Did H. erectus also have this remarkable aerobic endurance, and if so, how and why did this capacity arise?
Despite more than 130 years of research, it is still unclear exactly when, where, how, and why Homo erectus evolved. I contend that this may be in part due to a too narrow scope. So far, extinct hominins are seen as purely terrestrial species, not adapted to foraging in water. Yet, recent research shows that species like Neandertals already lived on the coast and dove underwater to collect molluscs for shells and food. There are several indications, notably its strikingly heavy bones, that suggest H. erectus could have been a shallow-water diver as well. My new research project centers on the question: Did H. erectus first evolve as a persistence-hunting endurance runner (per the traditional hypothesis), or rather —in response to severe inland aridity—as a forager for submerged aquatic resources along the Indian Ocean coast?