Every animal relies on a weapon of some kind -- cats have claws, eagles have talons, and even the dogs we keep as pets have a respectable set of teeth. But the overwhelming majority of these weapons stay small, proportional to the rest of the animals' bodies. In rare cases, however, we find species whose weapons have become stunningly outsized, some with tusks or horns so massive that the animals who wield them look like they should tip over or collapse under their bulk and weight. Weapons just as extreme have cropped up in walruses and narwhals, crabs, beetles, bugs and flies. What is it about these species? Why are their weapons so big? When does bigger become too big? Biology professor Douglas Emlen pulls readers into the worlds of these remarkable beasts, trekking through rainforests and mountain passes to unravel the mysteries of their weapons. Humans are animals, too, and no book on extreme weapons would be complete without an examination of our own arsenals. The parallels betwee