13. Poison Dart Frogs -
Indigenous to Central and South America, the poison dart frog might just be the most poisonous animal on the face of the Earth, with enough poison to kill ten humans (or 20,000 mice) stored inside their dainty two inch bodies. The species attained its name from South American natives, who harnessed their toxic secretions to poison the tips of their blow-darts, knowing that just a single drop on the head of a pin is enough to kill!