Newt
Newts, as with salamanders in general and other amphibians, serve as bioindicators because of their thin, sensitive skin and evidence of their presence (or absence) can serve as an indicator of the health of the environment. Most species are highly sensitive to subtle changes in the pH level of the streams and lakes where they live. Because their skin is permeable to water, they absorb oxygen and other substances they need through their skin. Scientists study the stability of the amphibian population when studying the water quality of a particular body of water.
Taricha
"Taricha" spp. eat a diet largely consisting of invertebrates, though adults will also take fish and amphibian eggs. Most predators associate bright colors with poison (called aposematism), so if attacked, the newt will take up a defensive position, showing off the bright underbelly. Newts of this genus are primarily nocturnal, and may be either fully aquatic or semiaquatic. None are fully terrestrial as they must enter the water to breed. Juvenile newts, which are known as "efts", are primarily terrestrial until they reach sexual maturity.