Kissing This Frog Won’t Get You a Prince!

By Carol Johnson

Everyone’s seen those movies with jungle tribes who kill interlopers by shooting them with darts tipped with poison. Ever wonder where they get that poison? Well, often they get it from the backs of tiny frogs. Because of the widespread notion that all the poison comes from frogs, the general name of these little toxic amphibians is poison arrow frogs, or poison dart frogs.

Most of the poisonous frogs are characterized by brilliant colors and complex patterns on their skin, which is used as a warning sign to predators. They are usually very small and are common in very tropical humid environments. In actuality, there are over 175 species of poison frogs, but only three are toxic enough to use for gathering poison for darts. Their backs ooze a glistening neurotoxin that is meant to keep natural predators away, and it is very successful in doing so. Each frog produces enough toxin to kill 10 human beings. The most poisonous is the Golden Poison Frog, which is only two inches long. This frog’s poison is an alkaloid, which is one of several poisons common to dart frogs. The poison prevents nerves from transmitting impulses correctly, so the muscles are left contracted and unusable. Such poisoning can quickly lead to heart failure.

The average potency of a frog’s toxin varies depending on its location, and consequently the local diet, but the average poison dart frog is estimated to produce about one milligram of poison—enough to kill about 10,000 mice, or 10-20 human beings. The alkaloid batrachotoxins stored in the frog’s skin glands can be stored for years even after the frog is deprived of a food-based source of the toxin. The poison does not deteriorate easily, even when it is transferred to another object. There are anecdotal stories of chickens, dogs, and other animals that have died simply from contact with a napkin a frog had walked on.

Because foods such as fruit flies and small crickets, which scientists can purchase, do not have the alkaloids required to produce the toxins, captive frogs do not produce the poison and eventually lose their toxicity. Additionally, captive-bred poison frogs are born harmless and poison-free. No one really knows what prey species in the wild gives the frogs their toxic alkaloid coating, but most of their diet in the wild consists of ants. However, herpetologists and hobbyists who keep poison frogs have reported that most of the frogs will not eat ants at all while they are in captivity. Scientists have postulated that the mystery insect that contributes the alkaloids to the frogs’ diet is a small beetle that lives in the Columbian rainforest. If this is the case, the little beetle may be the most poisonous creature in the world.

These deadly little frogs can live from 3 to 15 years in the wild, and up to 20 years in captivity. Surprisingly, it is usually not difficult to determine the sex of a frog by observing their behavior and looking closely at their body characteristics. Mature male frogs usually make a mating call after eating, which sounds like a series of high-pitched clicks. The backs of males usually slop down with less of a break than females, whose bodies are usually rounder. Females of some species have narrow toes, while the males’ toes are wide at the ends.

All species of poison dart frogs are tropical in origin, so the only ones in the United States are probably in zoos, research labs, or herpetologists’ collections. However, if you happen to encounter a brightly colored amphibian that glistens in the moonlight, it’s probably wise to dart away without giving it a kiss!