Scientists are confident that life exists elsewhere in the universe. But short of aliens landing in New York City, how do we know what they are like? Might there be an alien planet with supersonic animals? A moon where creatures have a language composed of smells? Using his own expert understanding of life on Earth and Darwin's theory of evolution, Cambridge zoologist Arik Kershenbaum explains how these creatures will move, socialize, and communicate, creating a mind-bending view of the possibilities of organic matter.