Golden Poison Frog

Golden poison frog is currently considered the most poisonous vertebrate worldwide.

The Golden Poison Frog's alkaloid poison, one of a number of poisons common to dart frogs, prevents nerves from transmitting impulses, leaving the muscles in an inactive state of contraction. This can lead to heart failure or fibrillation . Alkaloid batrachotoxins can be stored by frogs for years after the frog is deprived of a food-based source, and such toxins do not readily deteriorate, even when transferred to another surface. Chickens and dogs have died from contact with a paper towel on which a frog had walked.

The average dose carried will vary between locations, and consequent local diet, but the average wild P. terribilis is generally estimated to contain about one milligram of poison, enough to kill about 10,000 mice. This estimate will vary in turn, but most agree that this dose is enough to kill between 10 and 20 humans.

http://en.wikipedia.org/wiki/Golden_Poison_Frog

http://animaldiversity.ummz.umich.edu/site/accounts/information/Phyllobates_terribilis.html

http://www.amnh.org/exhibitions/frogs/vivarium/golden.php