With the rapid disappearance of some of the world's largest carnivores, prey populations in predator-free areas are becoming blasA©, perhaps too much so, according to [Gittleman and Gompper][1]. In their Perspective. They discuss new findings ([ Berger et al. ][2]) showing that reintroduction of large carnivores such as wolves and grizzly bears into areas containing their favorite prey, moose, results in an initial decline in moose numbers. Luckily, however, it turns out that moose are quick learners and within a single generation have acquired an array of antipredator behaviors. [1]: http://www.sciencemag.org/cgi/content/full/291/5506/997 [2]: http://www.sciencemag.org/cgi/content/short/291/5506/1036