Framed Frog

Anthony's poison-frog (Epipedobates anthonyi) seen through hole in leaf. Buenaventura Reserve, El Oro, Ecuador.

Photograph by Lucas Bustamante

When Ecuadorian biologist and photographer Lucas Bustamante spotted a group of tiny, fast-hopping Anthony’s poison-arrow frogs (Epipedobates anthonyi) in his home country’s Buenaventura Reserve, he was determined to capture the perfect shot. Lying in the leaf litter, where he inadvertently disturbed a swarm of feisty ants, he waited as quietly as possible until, at last, the moment came. A young frog perched, just for a moment, on the sunlit stage of a decaying leaf, and Bustamante had his picture.

Conspicuous as the juvenile frog was for those few seconds, it had nothing on its adult counterparts. When mature, Anthony’s poison-arrow frogs sport a candy-cane-striped pattern that practically leaps off the rainforest floor. The message to would-be predators? Don’t touch!

This bright warning coloration is no idle threat. The toxins the frogs secrete through their skin are 200 times more powerful than morphine. Like other members the poison dart frog family—a group made up of some 300 species—Anthony’s poison-arrow frogs acquire their toxins from their poisonous prey. After sequestering the toxic compounds they’ve ingested, the frogs secrete them through pores in their skin, which—with its bright colors—gives predators fair warning to stay away. Although scientists have not yet identified the specific source of this species’ toxins, they have traced the toxins found on other dart frogs to poisonous ants, beetles, and mites.

Pharmaceutical researchers have learned that in highly controlled doses, these skin secretions can serve as powerful painkillers. What’s more, unlike opioids, they’re non-addictive and don’t induce tolerance over time. Over the past decade, scientists have synthesized a number of derivative compounds that target specific pain receptors and therefore have the potential to be less toxic. Several of these derivatives are now being tested as new analgesic drugs.

Despite the formidable defenses it wields, Anthony’s poison-arrow frog is now classified as Near Threatened by the International Union for Conservation of Nature. Although it’s still relatively abundant in areas of southwestern Ecuador and northwestern Peru, the species is declining due to deforestation and the increased use of agricultural pesticides and other environmental pollutants. A potent reminder of the many—often unforeseen—ways that biodiversity can benefit humanity, this small frog is issuing a warning chorus. In this case, we still have time to listen.