Dead or Alive

Seven teenage boys on a wilderness-survival course startle a bear, and soon two of the group are critically injured.

National Geographic details two brutal shark attacks -- one of them fatal -- that left victims stunned and local communities on edge.

A veteran safari guide is attacked on the Zambezi River. Fourteen years later, Javier Franco's canoe is capsized on the same stretch of water.

A Californian billionaire's money is no protection against an elephant on the Serengeti, and a fisherman comes up against an angry male.

An outing in the California mountains turns violent when trail-goers meet the region's most notorious predator: the cougar.

In Florida, a landscape gardener is grabbed by the waist while working near a pond. Elsewhere in the state, a swimmer falls victim.