Humans evolved to be the water-saving ape. Duke Today, March 5, 2021. An ancient shift in our body’s ability to conserve water may have enabled early humans to venture farther from lakes and streams in search of food. So say the authors of a study that, for the first time, measures precisely how much water humans lose and replace each day compared with our primate cousins. Picked up by Inverse, MSN, UPI and Cosmos.