When life throws out a challenge to survival, animals have to come up with creative ways around it-or risk extinction. Their solutions are often ingenious-and stranger than anything we can imagine. The moray eel had to evolve a second set of teeth in its throat just to swallow. The Komodo dragon can kill with bacteria to make up for its weak jaws. And sand tiger sharks eat each other in the womb, so they can be born big and strong. In a world where only the fittest survive, the future belongs to these mutating problem-solvers.