The class amphibia includes frogs and toads (which make up the order Anura), and newts and salamanders (which make up the order Urodela). Amphibians typically have moist, scaleless, hairless skin; lungs; and are cold-blooded. They also undergo complete metamorphosis, from eggs laid in water through various water-living larval stages (such as tadpoles) to land-living adults. Typical features of adult frogs and toads include a squat body with no tail; long, powerful hind legs; and large, often bulging, eyes. Adult newts and salamanders typically have a long body with a well developed tail; and relatively short, equal-sized legs. However, newts and salamanders show considerable variation; for example, in some species the adults have minute legs, external gills rather than lungs, and spend their entire lives in water.
The class amphibia includes frogs and toads (which make up the order Anura), and newts and salamanders (which make up the order Urodela). Amphibians typically have moist, scaleless, hairless skin; lungs; and are cold-blooded. They also undergo complete metamorphosis, from eggs laid in water through various water-living larval stages (such as tadpoles) to land-living adults. Typical features of adult frogs and toads include a squat body with no tail; long, powerful hind legs; and large, often bulging, eyes. Adult newts and salamanders typically have a long body with a well developed tail; and relatively short, equal-sized legs. However, newts and salamanders show considerable variation; for example, in some species the adults have minute legs, external gills rather than lungs, and spend their entire lives in water.
