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.

The Brazilian yellow scorpion is one of the species' most venomous, but a tiny, parasite-bearing snail has a much bigger and more devastating effect.