Leaping into frog culture

Poison dart species on display at museum

by R. Peyton Hale

 

Travel to the New World Tropics of Central and South America, and you’ll find a diverse group of small and fascinating frogs hopping about during the daytime hours. Poison dart frogs are a group of roughly 250 species that are known for their brilliant warning coloration and distasteful skin toxins. Found from Nicaragua through Bolivia and eastward to the coast of Brazil, these frogs are dispersed across a wide variety of habitats, from cool, montane forests to the Amazonian lowlands.

 

Unveiled last spring, a new permanent exhibit in the North Carolina Museum of Natural Sciences’ Tropical Connections hall showcases these marvelous amphibians. Comprised of six species, 23 frogs reside in the fully planted vivarium, which features a variety of plant life from Central and South America. Center stage is a tall water feature that emulates a small tropical waterfall and creates a stream that travels to the front of the exhibit.

 

Frog knowledge

Despite their name, only one-third of poison dart frogs have toxins strong enough to act as a defense mechanism against predators. These toxins primarily are derived from the invertebrates in the frogs’ diet — ants, beetles, mites and small millipedes — although some milder forms are created by the frog regardless of diet. Most of the toxins are merely distasteful, but some can cause more serious effects, such as local paralysis, nausea, and even death. Frogs taken from the wild and housed in captivity have shown a decrease in toxicity below dangerous levels, primarily because their diets have been altered.

 

In a strange twist, the same toxins that protect these frogs from predators actually assist other predators. Members of the Embera tribe in Columbia, for example, rub blowgun darts on the skin of the golden poison frog, or Phyllobates terribilis, for hunting purposes. This species’ toxin is so potent that it can take down medium-sized game, and darts can remain lethal for up to three years.

 

Poison frogs also are known for their quality parental skills; many species will allow newly hatched tadpoles to wriggle onto their backs, and will transport them to temporary pools of water in trees or higher up into the water-filled axils of bromeliad plants. The flaming poison frog, or Oophaga pumilio, raises the parenting bar even higher. Both males and females guard the eggs until they hatch, then transport tadpoles to a safe location within the bromeliads. The female deposits infertile eggs every few days to feed her tadpoles until they metamorphose.

 

Saving the population

Frogs in the museum’s permanent exhibit come from amateur hobbyists and professional breeders across the country who are dedicated to raising and supplying healthy animals without causing a decrease in native populations due to overcollecting.

 

Many of these captive breeders have banded together to develop a professional protocol for maintaining and producing dart frogs. These protocols help to prevent the spread of infectious diseases such as chytridiomycosis to captive and wild populations. In the wild, this disease has become a serious threat to the dart-frog population, as well as all amphibians worldwide. 

 

R. Peyton Hale is curator of Living Collections for the North Carolina Museum of Natural Sciences in downtown Raleigh. To learn more about the exhibit, call (919) 733-7450 or visit www.naturalsciences.org.