Its bite force and night vision make the jaguar the jungle's "killer of killers", but the fer-de-lance pit viper's flesh-rotting venom is devastating.

Orcas possess awesome speed, power and intelligence, but the rattlesnake, black widow spider and even the mosquito challenge them in dangerousness.

Despite dwindling numbers, the Humboldt squid's beak is deadly, but the Brazilian wandering spider's fangs and venom are ruthlessly efficient.