So what brought about the demise of H. erectus on Java? Ciochon says it was likely climate change. A bunch of bones from animals found in open woodland environments, similar to Africa, were found alongside the fossils. The ecosystem changed into the rainforest that it is today — and it’s likely H. erectus wasn’t able to adapt. Of course, it’s impossible to know precisely when the species died out, but these young fossils are certainly a clue.