After rodents, bats are the second largest group of mammals, representing a staggering 20% of all mammal species. They can be found all over the world, with the exception of cold climates, where they often play incredibly important ecological roles. Their ecologies (ways in which they live) go well beyond the cave-hanging, moth-eating stereotypes and diets can also be based on fruits, nectar or even blood. In fact, some tropical plants rely solely upon bats for pollination! But when did bats evolve and who are their closest relatives? Do they have a good fossil record? Is vampirism an effective feeding strategy? In this episode, we're joined by Dr Nancy Simmons, Curator-In-Charge of Mammalogy at the American Museum of Natural History, who introduces us to the wonderful world of bats and their fossil record.