June 4 : The cave lion was one of the biggest cats to ever live, prowling a huge swathe of territory from Western Europe across Siberia and into North America and hunting large prey - and perhaps even people - before going extinct around the end of the Ice Age. New genome research reveals what made this big cat unique and how it differed from the modern lion, its smaller cousin, though the two species did sporadically interbreed. The cave lion, whose scientific name is Panthera spelaea, died