The word amphibian comes from the Greek word amphibios , meaning "a being with a double life. While dual residence is the rule for most amphibians, some species are strictly aquatic water-dwelling and some are strictly terrestrial land-dwelling. More accurately, amphibians' "double life" refers to two distinct life stages -- a larval stage and an adult stage. Most amphibians lay eggs, which hatch into larvae and undergo an amazing transformation or metamorphosis as they move from larval to adult stages.
For instance, tadpoles the larval stage of frogs have gills and a tail -- features that enable them to live underwater. During metamorphosis, tadpoles lose their gills and develop lungs so they can breathe out of 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. Amphibians, like reptiles, are ectotherms. This means that they cannot produce sufficient internal heat to maintain a constant body temperature.
Instead, amphibians' body temperature varies, depending on the surrounding temperature. So what does this mean for amphibians? It 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 too cold to even bask, amphibians may brumate. This means they're in a hibernation-like state, but they may have periods of wakefulness and even drink when necessary. Too much wind can dry their skin and dehydrate the animal. As a result, amphibians are the first to die off when their habitats are disturbed or contaminated with chemicals like weed killers. This is the main reason over half of all frog species are in danger of extinction.
From the National Geographic book, Animal Encyclopedia , All rights reserved. Surinam toad. Togo slippery frog. Puerto Rican crested toad. Dyeing poison frog. About Amphibians. Amphibians are small vertebrates that need water, or a moist environment, to survive.
Latest Amphibian Videos. Now Playing. And because many reptile species are long-lived and relatively slow-moving, they suffer from disturbances like habitat loss or pollution for extended periods. A diverse community of amphibians and reptiles indicates that the area is healthy and can support the plant and animal life that herps need for food and cover. At the Center for Biological Diversity, we also believe that amphibians and reptiles — and all species, great and small — deserve protection for their own sakes and because these amazing creatures help make the world a wonderful place for all of us to live.
Yes, the world's amphibians and reptiles are facing an unprecedented assault and are experiencing tens of thousands of years' worth of extinctions in just a century. Scientists have observed these disturbing trends in the United States too, where approximately 20 percent of amphibian species and 10 percent of reptile species are at risk of dying out.
While habitat loss is the most obvious cause of endangerment, declines are even even occurring in pristine areas from threats such as disease, UV radiation and climate change. Amphibians and reptiles are also suffering from overcollection and unregulated hunting. We need your help to protect these valuable species from further devastation. Here's how you can help herps:. Why care about amphibians and reptiles?
Are amphibians and reptiles in trouble?
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