All amphibians must live near water because their soft skin provides little protection against dehydration. If their skin dries up, they soon die. Most live in the areas between fresh water and dry land or in regions that have plenty of dew and moisture.
Some species of amphibians are active by day, while others move about at night. Their activity is also influenced by temperature and humidity.
Amphibians are cold-blooded animals, meaning they are about the same temperature as their environment. When the temperature drops or rises or the humidity falls, they change habitats in order to become more comfortable. This is necessary because their body temperature influences such processes as growth and egg formation.
Where temperature becomes high and humidity low, or where dry and rainy seasons alternate, some amphibians become inactive until conditions are again favorable. This is called aestivation.
In cold or temperate regions, some amphibians go into hibernation. They seek out mud, trees, or caverns in which they remain in a state of inactivity for periods ranging from two to eight months, until the environment is again warm enough (see Hibernation).
Some amphibians are considered moderately intelligent. They are known to communicate with each other by calls or croaks that indicate mating, distress, or territorial concerns. Sounds, which vary greatly among the species, are made by the passage of air across the vocal cords. Male frogs have vocal sacs on either side of the throat. These act to amplify sounds. Some frogs and toads even sing in chorus.
Frogs and toads have a strong sense of location. When taken from their territories or breeding grounds, they can find their way back by smell and instinctively by the position of the stars. Many migratory species tend to return to the same breeding grounds year after year.
Amphibians respond to danger in several ways. Some dive in the water or hide in dens. Others pretend to be dead or camouflage themselves by changing color. Others protect themselves with poisonous skin secretions, or puff up to look large and frightening. The enemies of amphibians include foxes, hedgehogs, storks, herons, snakes, and large spiders.
Humans are the most serious threat to amphibians. Although amphibians help keep insect populations under control, they are often destroyed when people drain marshes to kill mosquitos and other insect pests. Amphibians are eaten in some countries; frog legs are a delicacy. Many amphibians are used in scientific experiments. Some are also kept as pets.
Main Page - Kinds of Amphibians - Physical Characteristics - Behavior
The Evolutionary Record - Anatomy of the Frog