Vampire bats that regurgitate blood for roosting buddies. Mosquitoes that filch honeydew droplets from ants. Reptiles that enforce chastity on their lovers with copulatory plugs. Capuchin monkeys that use millipede secretions as mosquito repellent. The natural world is full of unusual relationships, and negotiation between life-forms striving to survive is evolution at its most diverse, entertaining, and awe-inspiring. Picking up where her...