Anurans (frogs and toads) communicate largely through sound. Every species has a unique vocalization or “call.” The sound is made by passing air through a part of the throat called the larynx, similar to how we make sound. Most frogs also have a pouch under their throats (vocal sacs) that stretch during calling to amplify the sound. Calling is used by males to attract females for mating. While males may call individually, in many species they gather in groups, resulting in a chorus of calls. Aggregating may give males the advantage of attracting more females, although then they must compete for them. There is evidence that females select males based on how loud and/or low they call, causing natural selection for powerful calls (sexual selection). Frogs also use sound to communicate distress (if grabbed by a predator), defend territories, or other events.

Amphibians lay eggs that have no shells and must stay moist to survive. Usually, the eggs are laid in water. The larvae that hatch out are aquatic, living in ponds or streams for at least some part of their life cycles. Gills allow them to get oxygen underwater. Their bodies are adapted for swimming, with large tails and small limbs or none at all. Most amphibians undergo a dramatic body transformation (metamorphosis) to become adults. They may absorb their tails and sprout limbs, grow sensory tentacles, and/or get thicker skin. Along with metamorphosis come changes in behavior and diet. For some species, larger mouths with teeth and tongues reflect the switch from algae-eaters to carnivores. For others, sticky toes mean they can climb trees and cling to leaves. While many adult amphibians still live in or near water, they have lungs and other adaptations to life on land.