But honey bees aren't the only bees out there. Earth is home to some 20,000 named species of bees, and there may be another 20,000 waiting to be discovered and named. We don't know much about these species, what they're like, or how they're faring in the "global pollinator crisis." In a new book, biologists Sam Droege and Laurence Packer shine a spotlight on some of that incredible bee diversity--for example, did you know that some bees have a tongue longer than their bodies, or that others drink sweat?--while also highlighting our shortage of knowledge about these important species. And they do it all through amazingly vivid images, as you can see in the gallery above.