Homo habilus, lived 2.3 to 1.5 million years old, and was the first tool maker. There is some debate about Homo habilus, because he could be the last and most developed of the Australopithecenes, being called Australopithecus habilus, or became a new and different Homo habilus genus (and there is also here Homo rudolfensis, of 2.4 to 1.5 million years ago, a variant species). Basically ice ages dried forests, so these humans ate meat (whereas before they ate vegetation) and they made and employed tools to cut animals. Meat diet made bigger brains and also hunting meant dependent children needing to learn how to hunt. Hunting is very active and so hair was shed to facilitate perspiration and cooling down.