6 Things You Didn't Know About Amphibians

Amphibians share the water with fish and the land with reptiles and mammals. Yet they're often treated like a forgotten middle child, as most people don't know much about these species beyond basic frog trivia. Get to know your amphibian pals.

1. Most go through an awkward youth.

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Well, that's awkward as in legless (and lungless). The majority of amphibians begin their lives in water with gills and tails instead of lungs and legs. While frogs famously begin life in tadpole form, it's important to note that salamanders and newts hatch as legless, wiggly little tadpoles, too!

And then there's the frog who shrinks as he develops. The paradoxical frog, Pseudis paradoxa, begins life as an enormous tadpole (up to 22 cm long) - nearly three to four times the length of post-metamorphosis adult frogs of the species!

2. The largest amphibian is the size of a full grown man.

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The world's largest amphibian species is the aptly named Chinese giant salamander. At 1.8 meters long (that's about 5'9") and weighing 50 kg, this species holds an important place within the collective culture of China, where it has been nicknamed "baby fish" (for its whining cry) and "pig not eat" (after farmers saw it being snubbed by hungry pigs even though it would make for easy prey).

3. The smallest amphibian makes a dime look huge.

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The 2012 discovery of the Paedophryne amauensis frog in Papua New Guinea was groundbreaking for multiple reasons. In addition to claiming the title of "World's Smallest Frog," this species is also the tiniest known vertebrate in existence. At just 7.7 millimeters in length, scientists tracking the high-pitched mating call of male P. amauensis estimated that the frogs may be living as close as 50 centimeters from each other - an unparalleled proximity within the habitat of vertebrates of any size.

4. Some amphibians are oversized earthworm doppelgängers.

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Amphibians are divided into three groups: frogs and toads, salamanders and newts, and caecilians. Though most people are familiar with those first two categories, few encounter caecilians (unless they are specifically sought out). Large, earthworm-resembling amphibians, caecilians spend most of their lives underground burrowing through loose soil. They range in size from three inches to nearly 5 feet.

Caecilians have a unique, bizarre way of nursing their young. After giving birth, mothers develop a thick, fatty extra layer of skin that their young feast on for the first several weeks of their lives. The process is called dermatotrophy and is the caecilian's version of producing milk for her young.

5. They're the first warning sign that something is wrong with the planet.

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Due to their permeable skin and reliance on clean environmental conditions for reproduction, amphibians are viewed as crucial ecological indicators. Amphibians breathe and drink with their skin, so they've evolved resistances to numerous bacteria and other hazards within their environment. But, when faced with man-made chemicals, they are defenseless. Before human pollution within their habitat nears a devastating tipping point, amphibians are the first to display the harmful effects of the waste that will inevitably effect every other species in the area.

6. If we aren't careful, we may lose them forever.

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Scientists estimate that a staggering one-third to one-half of Earth's known amphibian species could very well be extinct within our lifetime. According to the International Union for Conservation of Nature, at least 42 percent of all amphibians are declining in population - opposed to the 1 percent of amphibian species that displayed population increases. Habitat loss, climate change and epidemic fungal disease are prime culprits. These startling statistics are an ominous harbinger of oncoming struggles for countless other species as humans continue to impact and alter ecosystems all over the world.