Amphibians
Did you know that the word amphibian comes from the Greek word amphibios, meaning “a being with a double life”? Some say that their name refers to the fact that amphibians live in two places- on land and in water. Others say their “double life” refers to their two distinct life stages – a larval and an adult stage. There are more than 6,000 species of amphibians living today. This animal class includes toads and frogs, salamanders and newts, and caecilians.
Almost all amphibians have thin, moist skin. No other group of animals has this special skin. Their skin allows liquids and gases to pass through it easily. That means oxygen passes through their skin easily, helping them breathe. It also means they lose a lot of water through their skin. This is why most amphibians are found in moist or humid environments.
The Double-Life
Most amphibians lay eggs, which hatch into larvae and later undergo an amazing transformation. During this metamorphosis they move from a larval to adult stage. For example, frogs start out as tadpoles. They have gills and a tail enabling them to live underwater. During metamorphosis, tadpoles lose their gills and develop lungs so they can breathe out of the water. At the same time, they begin to grow limbs and lose their tails. The end result: adult frogs who spend much of their time on land.
Warming Up and Keeping Cool
Amphibians, like reptiles, are ectotherms. This means that they’re responsible for regulating their own body temperature. When it’s cold outside and they need to warm up, amphibians often bask in the sun to raise their body temperature. When it’s hot outside, amphibians spend much of the time burrowing during the day to keep cool, becoming active only at night.
Amphibians in Danger: The Threat of Extinction
Today, Amphibians are in crisis and need our help! At this very moment, amphibians are facing an extinction crisis. Over 160 species of amphibians may already be extinct. More than 1,800 amphibian species are threatened with extinction – that’s 32% of all known amphibian species. The greatest threat facing amphibians is habitat loss and degradation. Pollution, climate change, introduced species, and over-collection are all significant threats. Additionally, a newly-recognized fungal disease is causing rapid and severe amphibian declines.
What can be done to help amphibians?
As a first step, hundreds of experts have contributed to a Global Amphibian Assessment, an ongoing project that looks at the distribution and conservation status of all known amphibian species. In addition, experts and institutions have joined together to form the Amphibian Rescue and Conservation Project, which aims to rescue and possibly save numerous species. Amphibian specialists around the world are working on understanding the causes of the declines, developing long-term conservation programs, and responding to immediate crises.
Why should we help?
Amphibians have been referred to as “canaries in the global coalmine” and “nature’s indicators” because they are some of the first living things to be affected by environmental changes. A decline in the number of amphibians serves as a warning to other species, including humans. When we help amphibians, we are helping the world.
