Invasive species can be ruthless. Surprisingly, they can also be adorable. When non-native plants, animals, and pathogens are introduced into a favorable new environment, they can sweep through the ecosystem and threaten the survival of the native flora and fauna. They also wreak havoc on the economy. From Burmese python to Asian carp, efforts to eradicate or control invasive species cost U.S. taxpayers an estimated $138 billion per year. But in one notable case, humans have been happy to make an invasive species feel at home. We're talking about cats: one of the most prolific invasive species in history. The...