why is the lack of "fur" positive Progression for humans?

We also find flint spearheads on land and the bones of what seem to be butchered miniature elephants. This would argue for a pack hunter.This lends itself to the next clue. Evaporative cooling. This process is greatly enhanced by the removal of fur. It allows humans to hunt mammalian prey during the hottest hours of the day. During these hours these mammal species are usually cooling off in the shade. In fact, humans can chase prey for hours on end until that animal collapses from heat fatigue. This allows humans to hunt prey that is faster than they are by using endurance and our adaption to the heat which is sweating.

Then who was making the spearheads and butchering elephants inland, well away from the water? Was there another hominid species on the island that we are not aware of?