If Florida ever wants to rid itself of Burmese pythons, tegus and other slithery invaders, pray for cold. A new University of Florida study has confirmed what scientists have long suspected: temperature, more than habitat, determines where reptiles invade. Using the kind of risk assessment strategy normally used in business, researchers modeled where invasive lizards and geckos were likely to occur based on native habits, then compared that to where they live in Florida. Temperature, it turns out, creates an invisible barrier. And that means South Florida will likely remain the nation’s hottest spot for all things invasive.