[The Conversation Africa] Some 4.5 million years ago, during the early Pliocene epoch, Kenya's Lake Turkana looked very different than it does today. Grasslands and open woodlands were spreading in cooler, drier climates. Competition for C4 grasses - the kind that grow in seasonal, tropical environments and were well adapted for these new, cooler, drier conditions - was increasing between mammals like horses, hippos, rhinos, antelopes, pigs and elephants. Some of the oldest bipedal human ancestors, Australopithecus anamensis, inhab
