Is that a leaf or a frog? These masters of camouflage are called Darwin's Frogs after the famous father of evolution Charles Darwin, who discovered the species in 1834 in Chile. Darwin was on a voyage around the world on the HMS Beagle when he documented its existence. The frog species known as the northern or Chilean Darwin's frog is thought to be extinct since 1980.
But of concern now is another closely related cousin called the southern Darwin's Frog that is native to south-central Chile and Argentina, that appears to be now threatened due to loss of habitat.
Easily mistaken for a dead leaf with a pointy nose, the tiny amphibians have evolved their appearance to escape predators and ambush insects that they prey on.
They have long fleshy points on their snouts that give their heads a distinct triangular shape. The skin on their backs varies in color from green to brown. These frogs are barely an inch long with the females slightly longer than the males. When threatened, Darwin’s frog rolls over on its back and plays dead.
Peculiarly, the male Darwin's frog has an unusually large vocal sac and one would expect them to have a loud call. But they are there for a special reason.
Darwin's frogs have unusual brooding habits. They reproduce through a method not seen in any other amphibian. As soon as the females lay their eggs, the male takes over. He first gobbles up the eggs and stores them in his vocal sac. While the Chilean Darwin’s frog merely carries the tadpoles to a nearby pond or stream and releases the tadpoles to grow independently, the southern Darwin’s frog species goes a step further. The male keeps the tadpoles in his vocal sac until they emerge from his mouth as much as 50 days later as fully-developed froglets. Talk about daddy care!
Frogs And Our Eco-system
Frogs are sensitive bioindicators. Their skin has the ability to absorb toxic chemicals. In recent times, the wild environmental disturbance is upsetting their population. Skin secretions from frogs are very important in medical research. Nearly 10% of all Nobel prizes in physiology and Medicine have resulted from investigations that used frogs. You may find frogs slimy, but did you know they play an important role in our eco-system? They form an important part of our food web. Besides eating insects that can transmit fatal illness to humans, they are also a source of food for other predators that make up the intricate food web.
The importance of these amphibians can scarcely be underplayed for us humans. For our own sake, it is important that we take steps to preserve the biodiversity of our world.
Courtesy: BBC, National Geographic