A female Anopheles quadrimaculatus mosquito takes a blood meal from a host. For millennia, this mosquito has spread malaria. Researchers now think that these mosquitoes — and the disease they carry — played a critical role in determining where ancient humans settled and whether they thrived or failed to thrive. Smith Collection/Gado via Getty Images hide caption toggle caption Smith Collection/Gado via Getty Images For tens of thousands of years, where humans have chosen to live has long been shaped by climate and the landscape. That's why there are so few of us clinging to the crags of Mount Everest or decamping to Antarctica. And the places we have called home in more welcoming parts of the world have helped shape our species — from our genes to our behaviors. "How we became human is a story that played out over a very deep time scale and over a very big area," says Eleanor Scerri , an evolutionary archaeologist at the Max Planck Institute of Geoanthropology in Germany.…