The cave entrance. (Chris Grooms) You may not give a pile of bat poop gathered over 4,300 years a second look – but to a group of scientists, it's provided an intriguing insight into how bat diets and therefore climate conditions have shifted over thousands of years. Taller than the average man (2 meters or 6-and-a-half feet), the pile of poop (also known as guano) records history in clear layers, much like sediments under a lake. By analyzing the layers back through time, the scientists have been able to figure out changes in the diets of the bats that have...