I think the word you guys are searching for is "troglodyte". See
http://www.youtube.com/watch?v=VlRXQEA0yj0 On a (somewhat) more serious note: it would be entirely consistent with global warming theory if the rapid extinction of large Pleistocene mammals (woolly mammoth, sabretooth, etc) were caused by the flatulence of those very mammals.
Think about it. Global Warmists/Vegans complain bitterly about the methane generated by livestock raised for us carnivores. They routinely claim that eating meat increases global warming because of the methane flatulence generated by cows & pigs. Now imagine the amount of methane that must have been released by millions of mammoths, mastodons, woolly rhinos, giant sloths, etc, etc.. According to the Global warmists, this massive methane production would have created rapid warming, followed by the shut-down of the oceanic thermo-haline conveyor in the north Atlantic, which would plunge the earth into a rapid new ice-age.
It's a better theory than the theory that a few thousand humans hunted millions of mammoths to extinction (cuz killing mammoths with stone spears was so easy).