Examining evidence about Neanderthals that sheds light on the hominids, which died off some 30,000 years ago. Included: geneticist Svante Pääbo's 2010 reconstruction of the Neanderthal genome, which posits that modern humans and Neanderthals interbred at some point in the distant past.

Over the last few centuries we have shot, trapped, and skinned the predators that formerly thrived at the top of the food chain in the wild. Wild bears, wolves, and big cats are all in retreat, and a growing number of scientists are discovering that by eliminating predators, we have changed the environment. Removing predators from the wild has thrown ecosystems off-kilter, triggering domino effects that scientists are just beginning to understand. In "Wild Predator Invasion," NOVA follows scientists who are trying a simple but controversial solution: returning apex predators—like wolves, bears, and panthers—to their natural environments. Can these newly reintroduced predators restore the natural balance of their ecosystems without threatening the humans who live among them?