Based on a best-selling novel, Zoo told the story of a heroic group of scientists, animal experts, a journalist and an Interpol agent who take on the biggest crisis the world has ever seen: animals smart enough to realize how terribly we're screwing up the planet, who eventually decide humans must DIE. Scary, right?
Unfortunately, this totally bananas premise didn't merit a huge viewership, and the show's numbers steadily declined during its three-season run. It was, however, the longest-running original summer scripted drama on CBS (tied with Under the Dome), which is probably a small consolation prize but noteworthy nonetheless. The decision to axe Zoo comes on the heels of Salvation's Season 2 renewal. Apparently there's only enough room for one impending apocalypse on the CBS summer lineup.