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

Creatures such as the tarantula and the Gila monster are nightmares of myth and legend -- but also a surprising treasure trove for medical science.

The oceanic whitetip shark is infamous for attacking shipwreck survivors. On land, packs of feral dogs are becoming a serious threat to human life.