In the animal kingdom, females are tough, feisty and fearless. But these lady-killers don't just get by on their good looks; they use their paws, claws and jaws to ensure survival – for themselves and their offspring. From the fierce protectiveness of a mama grizzly bear, to the cunning teamwork employed by lady lions – this hour of WORLD'S DEADLIEST is dedicated to the KILLER BITCHES. http://channel.nationalgeographic.com/wild/episodes/lady-killers/

Some you see and some you don't, but they all have eight legs and bulging eyeballs. This is a nightmare of the arachnid kind.

A look at the jaws, poison and powers of the nightmarish creatures lurking in the world's seas.

Wrangling snakes is more art than science, and the stakes are high. Get ready to go hand-to-scale and face-to-fang with cold-blooded killers.