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Have you ever heard the sound of frogs

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calling at night?

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For hundreds of millions of years,

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this croaking lullaby has filled the nighttime air.

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But recent studies suggest

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that these frogs are in danger

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of playing their final note.

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Over the past few decades,

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amphibian populations have been rapidly disappearing worldwide.

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Nearly one-third of the world's amphibian species

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are endanger of extinction,

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and over 100 species have already disappeared.

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But don't worry, there's still hope.

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Before we get into how to save the frogs,

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let's start by taking a look

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at why they're disappearing

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and why it's important to keep them around.

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Habitat destruction is the number one problem

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for frog populations around the world.

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There are seven billion humans on the planet,

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and we compete with frogs for habitat.

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We build cities, suburbs, and farms

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on top of frog habitat

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and chop forests

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and drain the wetlands

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that serve as home

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for numerous amphibian populations.

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Climate change alters precipitation levels,

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drying up ponds, streams, and cloud forests.

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As the Earth's human population continues to grow,

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so will the threats amphibians face.

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There are a variety of other factors

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contributing to the frogs' decline.

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Over-harvesting for the pet and food trade

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results in millions of frogs

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being taken out of the wild each year.

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Invasive species,

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such as non-native trout and crawfish,

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eat native frogs.

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Humans are facilitating the spread

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of infectious diseases

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by shipping over 100 million amphibians

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around the world each year,

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for use as food, pets, bait,

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and in laboratories and zoos

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with few regulations or quarantines.

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One of these diseases,

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chytridiomycosis,

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has driven stream-dwelling amphibian populations

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to extinction

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in Africa,

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Australia,

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Europe,

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and North, Central, and South America.

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On top of all these problems,

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we add hundreds of millions of kilograms of pesticides

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to our ecosystems each year.

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And these chemicals are easily absorbed

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through amphibians' permeable skin,

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causing amino suppression,

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or a weakened immune system

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and developmental deformities.

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Okay, so why are these little green guys

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worth keeping around?

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Frogs are important for a multitude of reasons.

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They're an integral part of the food web,

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eating flies, ticks, mosquitoes,

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and other disease vectors,

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thus, protecting us against malaria,

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dengue fever,

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and other illnesses.

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Tadpoles keep waterways clean

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by feeding on algea,

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reducing the demand

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on our community's filtration systems

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and keeping our cost of water low.

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Frogs serve as a source of food

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for birds, fish, snakes, dragonflies, and even monkies.

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When frogs disappear,

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the food web is disturbed,

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and other animals can disappear as well.

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Amphibians are also extremely important

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in human medicine.

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Over ten percent of the Nobel prizes

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in physiology and medicine

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have gone to researchers

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whose work depended on amphibians.