Frogs lost their toxins in captivity
Scientists are attempting to restore the toxicity of frogs from the Atelopus group, native to Central and South America, to protect them from predators. These frogs are naturally toxic, with a single frog carrying enough poison to kill thousands of mice. However, many have been bred in captivity after their populations were devastated by a fungal pathogen, the deadliest wildlife disease in recorded history.
In 2017, the Panama Amphibian Rescue and Conservation Project released 83 captive-bred frogs into the wild. While captivity shielded them from the fungus, it led to an unexpected drawback: the frogs lost their toxins, making them easy prey.
Research aims to make frogs 'spicy' again
Conservation biologist Brian Gratwicke of the Panama Amphibian Rescue and Conservation Project said: 'How can we make these frogs spicy again?' Scientists are now investigating how to restore toxicity in wild frogs so they can defend themselves. The first step is identifying the toxins present in wild frogs and measuring their levels, then comparing them to those in captive frogs to see if any original toxins remain.
Chemist Phillip Jervis from Imperial College London collected samples from several dozen frogs during a secondment at the Smithsonian’s lab in Panama. He placed each frog in a plastic bag with a stress hormone to stimulate toxin release. He is now analyzing these samples to compare toxin levels between wild and captive-bred frogs.
Uncertainty about toxin source
It remains unclear how frogs become poisonous in the first place. Scientists suggest the toxins may come from their environment, algae, or something in the food chain. Researchers are also studying whether previously captive frogs can regain toxins simply by returning to their natural habitat. In an experiment, scientists fed frogs moths that had been injected with toxins. Although the frogs survived ingesting the insects, it is uncertain whether this method can restore toxin levels to those seen in wild frogs.
