[00:07] Frogs, toads, salamanders, and other amphibians are among nature's most sensitive indicators of our planet's health.

[00:14] Amphibians have permeable skin and are extremely susceptible to toxins in the air and water, and to slight changes in temperature and humidity.

[00:22] Today, about one third of the nearly six thousand species of amphibians known to exist on Earth are threatened with extinction.

[00:29] Like the canary in the mine, their declining fate sounds a powerful alarm.

[00:34] The most dramatic loss of amphibian species has occurred in the past quarter century.

[00:38] While pollution and loss of habitat are major causes of amphibian decline, some large-scale die-offs have occurred in relatively undisturbed environments.

[00:47] In the late 1980's, scientists noted that several tropical frog species disappeared immediately following periods of unusually warm temperatures.

[00:56] An explanation is that in the tropical forests of Costa Rica, warm, dry weather nurtured a deadly skin fungus that drove the Golden Toad and Monteverde Harlequin Frog to extinction.

[01:06] As Earth's temperature rises, other infectious diseases are expected to spread more widely; diseases that affect species other than amphibians.

[01:14] Because amphibians suffer the effects of environmental change before many other forms of life, their staggering decline sounds an alarm about the fate of all species on the planet. It's time we listen to the message they are dying to send.