Golden Poison Frog - Poison

Poison

The golden poison frog's skin is densely coated in alkaloid poison, one of a number of poisons common to dart frogs (batrachotoxins), which prevents nerves from transmitting impulses, leaving the muscles in an inactive state of contraction. This can lead to heart failure or fibrillation. Some native people use this poison to hunt by coating darts with the frogs poison. 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 golden poison frog is not venomous, but poisonous; venomous animals have a delivery method for the toxin, such as fangs or spines, poisonous animals and plants do not have a delivery method and rely on transference of the toxin. Like most poison dart frogs, P. terribilis uses poison only as a self-defense mechanism and not for killing prey. The most venomous animal is the sea wasp jellyfish, which is slightly less toxic than P. terribilis.

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 this dose is enough to kill between 10 and 20 humans, which correlates to up to two African bull elephants. This is roughly 15,000 humans per gram.

This extraordinarily lethal poison is very rare. Batrachotoxin is only found in three poisonous frogs from Colombia (genus Phyllobates) and three poisonous birds from Papua New Guinea: Pitohui dichrous, Pitohui kirhocephalus and Ifrita kowaldi. Other related toxins are histrionicotoxin and pumiliotoxin, which are found in frog species from the genus Dendrobates.

The golden poison frog, like most other poisonous frogs, stores its poison in skin glands. Due to their poison, the frogs taste vile to predators; P. terribilis poison kills whatever eats it, except for a snake, Liophis epinephelus. This snake is resistant to the frog's poison, but is not completely immune.

The poisonous frogs are perhaps the only creatures to be immune to this poison. Batrachotoxin attacks the sodium channels of the cells, but the frog has special sodium channels the poison cannot harm.

Since easily purchased foods such as fruit flies and extra-small crickets are not rich in the alkaloids required to produce batrachotoxins, captive frogs do not produce toxins and they eventually lose their toxicity in captivity. In fact, many hobbyists and herpetologists have reported that most dart frogs will not consume ants at all in captivity, though ants constitute the larger portion of their diet in the wild. This is likely due to the unavailability of the natural prey species of ants to captive frog keepers. Though all poison frogs lose their toxicity when deprived of certain foods, and captive-bred golden poison frogs are born harmless, a wild-caught poison frog can retain alkaloids for years. It is not clear which prey species supplies the potent alkaloid that gives golden poison frogs their exceptionally high levels of toxicity, or whether the frogs modify another available toxin to produce a more efficient variant, as do some of the frog's cousins from the genus Dendrobates.

Thus, the high toxicity of P. terribilis appears to be due to the consumption of small insects or other arthropods, and one of these may truly be the most poisonous creature on Earth. Scientists have suggested the crucial insect may be a small beetle from the family Melyridae. At least one species of these beetles produces the same toxin found in P. terribilis. The beetle family Melyridae is cosmopolitan. Its relatives in Colombian rainforests could be the source of the batrachotoxins found in the highly toxic Phyllobates frogs of that region.