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 marches to kill mosquitos and other insect pests. Many amphibians are used in scientific experiments. Some are also kept as pets. Most amphibians begin their lives in the water as tadpoles, or larvae, which breathe by means of external gills instead of lungs. At firstthe tadpole has no definite shape, and no tail can be seen.