Hundreds of animal species famously died out during the last Ice Age. The reasons behind the Ice Age, Pleistocene, or Quaternary, megafaunal extinctions have been puzzled over for more than a century without any clear resolution. The problem has been called the 'Fermat’s Last Theorem of paleobiology'. These extinctions took place over thousands of years and around the world, but there was a strange specificity about which animals could stay and which had to go. There are two major theories about what caused this, the human-hunting theory and the climate-change theory. Both, yet in curious ways, are wrong. The true cause has to do with particular strengths and weaknesses of biological processes, and it unfolded over almost the entire history of life on Earth.
