The rainforest is home to the largest amount of diverse amphibians in the world. There are over 2,100 known species of frogs, alone. Researchers believe that there are many more species of amphibians not yet discovered. But the race is on, because these fragile creatures are rapidly heading towards extinction.
Current projections show that over 40% of all amphibians in the Central America are threatened. 337 species are listed as being on the verge of extinction. 117 species are listed as possibly extinct, which means that scientists haven't been able to find any populations of the species although a thorough search has not yet been performed. Last year, a species of frog that hadn't been sighted in 14 years, the Carrikeri Harlequin frog, was re-discovered in Colombia. Scientists are hopeful that more of the "possibly extinct" species will be found.
There are many theories that explain the decline of amphibians and scientists believe that it's usually a combination of factors. Destruction of the rainforest is a major contributor to extinction. Deforestation causes a loss of habitat, disrupts the food chain, and can have a disastrous effect on every aspect of amphibian life. For example, poison dart frogs lay their eggs in water plants. If these plants are killed during deforestation, the frogs are unable to reproduce.
Amphibians are extremely susceptible to pollution and changes in climate. Their skin is porous, allowing environmental toxins to seep through their whole body. Many depend on very specific conditions. Small changes in the average temperature can wipe out whole species. Frogs are actually called indicator species by scientists because their health can predict our planets health. They are often the first to react to changes in the environment.
Disease is another risk factor and the most deadly is a fungus, chytridiomycosis, which is believed to be gaining strength due to global warming. It isn't a new fungus but it's suddenly wiping out huge pockets of amphibians worldwide. Scientists think that higher average temperatures combined with more rainy days has helped the fungus to thrive.
It's easy to overlook the importance of amphibians. They may not be as appealing as a panda bear, as engrossing as a gorilla or as awe inspiring as a Killer Whale, but their survival is just as important as all of those. The more you learn about the unique amphibians of the rainforest, their true value becomes more apparent.
Poison Dart Frogs are the most well known of the rainforest amphibians. They are not currently on the endangered list thanks to successful breeding programs in zoos around the world, but their numbers are declining in the wild. There are 75 different species of Poison Dart Frogs. They come in a variety of colors. Most often they are black, green or blue with stripes or spots that are green, blue, yellow or white. The bright colors serve as a warning to potential predators. They secrete a toxin from glands on their back. Most people have heard that rainforest Indians dip their arrows and spears in the poison to aid in hunting, but few people know that that poison has also made its way into modern medicine.
In 1974 a researcher named John Daly discovered that the poison secreted by these frogs worked as a pain reliever in humans. The substance, which he named epidatidine, is 200 times more powerful than morphine and unlike other powerful pain relievers it doesn't cause drowsiness. Deciding that more testing was necessary to ensure epidatidine was safe, John Daly tried breeding the frogs in his lab. Unfortunately their offspring didn't produce the toxin. It wasn't until 1990 that scientist had the technology to break down a sample of epidatidine and duplicate its structure. The result is ABT-594, a non-addictive potent painkiller that has few side effects.
That is an example of the power of one rainforest amphibian. Imagine how many others have gifts to bestow on us. There are species that have never been discovered, and species that are going extinct before we have a chance to view their full potential. They may be little, but they play an important role in both the food chain and life on this planet.