A friendly-looking but deadly seal prowls the frigid waters off the tip of South America. The recluse spider's sting is painful, then rots away flesh.

The murky rivers of the tropics contain a shocking surprise: the electric eel. The cute capybara and the furry llama can be surprisingly treacherous.

The elephant seal's crushing head-butt is a killer skill, but the bites of both the Amazonian giant centipede and the vampire bat are horrifying.