Newts are a subgroup of salamanders; so a salamander is not always a newt. Salamander, in fact, is the name for all amphibian adult species with tails, including olms, spring lizards, water dogs, mud puppies and newts. There are very few things, however, that distinguish a a newt from other salamanders.
The three categories of salamanders are: totally aquatic, semi-aquatic, and completely terrestrial, with the latter spending their full lives on land. Overall, many newts are aquatic and tend to spend much of their adult lives in the water. Many species of salamanders spend much time on the land and can be found in shady forested areas and keep out of the sun. You can find them under logs, rocks, in trees and burrowed in the damp earth.
Female salamanders that spend more time in the water lay up to 450 eggs, many more than salamanders that live mostly on land. Newts are mostly aquatic and begin their life stages in the water. Some species of newts, such as the California newt, lays clumps of seven to 30 eggs on underwater plants.
Since newts are a subgroup of salamanders, a salamander is classified as a newt if it falls under one of the following genera: Cynops, Echinotriton, Euproctus, Neurergus, Notophthalmus, Pachytriton, Paramesotriton, Pleurodeles, Taricha, Triturus or Tylototriton. Some examples falling under these categories are the fire belly newt, Anderson's crocodile newt, black spotted newt and the Himalayan newt.
The skin of a newt tends to be more course and rough, unlike other salamanders, which are moister and slimier. Many newts are also brighter in color than other salamanders. In the case of predators, newts are seldom harmed for they are capable of excreting skin toxins, which predators find irritating. Some salamanders have the ability to drop their tails in the case of danger, and the tails grow back later.