Brazilian ranchers are turning up dead, gored by some unknown creature. There's a wide range of animal suspects from jaguars to caimans, but could the killer be something no one suspected?

In the jungles of Luzon Province, locals believe a vampire-like evil spirit has begun picking off villagers and livestock, taking them away without a trace. But could this in fact be new behavior from a frightening jungle predator?

Kangaroos are being mauled in Victoria, Australia. The wounds mimic those seen by lions, tigers and cougars in other parts of the world, but there are no big cats in Australia. Has a long-extinct predator returned?

Crocodiles, the apex predator of Australia's Northern Territory, are mysteriously showing up dead, belly-up in the water, with no clear sign of visible trauma. What could be taking down this vital animal with no known predators?

In Ecuador, a spree killer is loose in the wild as cows and other livestock are being mutilated in terrifying ways and left uneaten. Could it be proof the mythical Andean Mountain Wolf could in have some basis in fact?