Class: Amphibia (Amphibians)
Body length: 0.4 to 2.4 inches (1 to 6 centimeters), depending on species Weight: 0.02 to 0.14 ounces ( 0.5 to 4 grams), depending on species
Life span: 5 to 12 years in zoos; little is known about wild frogs
Incubation: 2 to 4 weeks. It takes 6 to 12 weeks for a tadpole to metamorphose into an adult frog, depending on the species
Number of eggs laid: 2 to 30, depending on species
Age of maturity: 1.5 to 2.5 years
Conservation status: many are at critical risk, including the red-banded poison frog Dendrobates lehmanni, and skunk frog Aromobates nocturnus.
Poison frogs can be confused with mantellas, which are also small and brightly colored but are less poisonous and native to Madagascar.
The golden poison frog Phyllobates terribilis is considered to be the most poisonous animal in the world, producing enough nerve toxin at once to kill 10 humans!
The frogs' Latin family name, Dendrobatidae, means “one who walks in the trees.”
Amphibians: Poison Frog
Here I am—don’t eat me!
Poison frogs are tiny, terrestrial frogs found in warm Central and South American rain forests. Bright coloring—in shades of red, orange, yellow, blue, green, and black—helps to protect the bite-sized diurnal frog. Those eye-catching colors scream out “Hey! Here I am and I am poisonous, so don’t even think about eating me!”
Look, but don’t touch!
Poison frogs are often called poison dart frogs because the Choco Indians in South America use the frogs' poison to coat the tips of the blow darts they use for hunting. You'll also hear poison frogs called "poison arrow frogs," but that's not accurate. The South American tribes that hunt with arrows usually coat their arrow tips with plant poisons, not frog poisons.
The deadly poison is found in the frog's skin, making it too toxic to touch. The Indians pick them up with waxy leaves and then dip their blow dart in the frog's skin secretions. Just a tiny drop can kill the birds and small mammals that the Indians hunt for food.
No larger than a bottle cap, a single golden poison frog Phyllobates terribilis can supply enough poison for 30 to 50 darts, and the dart's poison remains active for up to a year. Scientists know of only three frog species used for this purpose, so they suggest calling the family “poison frogs” rather than “poison dart frogs.” Many species of this family are not at all toxic to animals or humans.
You are what you eat
The poisons in these tiny frogs come from their diet in the wild: mostly ants, termites, centipedes, and tiny beetles. Toxins are passed from the bugs to the frog when eaten, then collected in glands in the frog’s skin. Frogs hatched at zoos aren’t poisonous because they don’t eat the same food as their wild counterparts; frogs brought from the wild into zoos and fed a regular zoo diet eventually lose most, if not all, of their toxicity.
Most frog species are nocturnal, but poison frogs are active during the day, when their jewel-colored bodies can best be seen and avoided. The frogs are very social and often stay in pairs or small groups. Males wrestle over territories, females tussle over the best egg-laying sites, and courting pairs nudge and caress one another with their chins and forearms. Things are seldom dull in the poison frog world!
Papas and piggyback rides
Poison frogs are also unique among amphibians because they are very involved parents and contribute a lot of energy to caring for their eggs and offspring. Frogs in the Colosthetus genus, for instance, lay their eggs on the forest floor or on the edge of a leaf. The male guards the eggs until they hatch, then the tadpoles wriggle onto his or the female's back. They are then carried to a water source, such as a pond or bromeliad (a type of plant). Females of other species often return to the tadpoles to lay unfertilized eggs that serve as a food source for the growing youngsters. Other poison frog species lay their eggs directly in water but continue to look after the eggs and tadpoles. And some, like the blue poison frog Dendrobates azureus, tend to eat their siblings as tadpoles, so the parents must find a different water source for each individual hatchling.
Take two frogs and call me in the morning
Scientists have been investigating medical uses for frog poisons. One laboratory has developed a new painkiller from the substances produced by the phantasmal poison frog Epipedrobates tricolor. Named “epibatidine” in honor of the frog, it is 200 times more effective than morphine without all of the bad side effects! Poison frog secretions also show promise for the development of muscle relaxants and heart stimulants.
Conservation is the key
These fascinating and beautiful little frogs are threatened by overcollection and the loss of their rain forest habitat. While some poison frog populations are considered stable, the populations aren’t large and their habitats are rapidly shrinking. A recently identified disease (chytridiomycosis) has depleted frog populations in Central and South America.