Watch Sadisflix. Fascinating footage of swooping bats, their remarkable habits and habitats, and close-up looks at their interesting yet eerie faces are featured in this documentary, volume seven of the Predators of the Wild series. Most bats eat insects, which may not always come to mind when one thinks of predators and prey -- although the fact that a swarm of bats can eat 30,000 pounds of insects in one night is staggering. Bats make up almost one-fourth of all of the mammals in the world, but only three species of bats are "true vampires" who rely on the blood of other animals for sustenance.