The difference between a newt and a salamander is that the newt often has an extra stage in its life cycle. Unlike the salamander, it spends two or three years of its life on land as a red eft. Then it returns to the water, where it spends the rest of its life. Most mature salamanders are terrestrial, though they need a moist environment.
Both newts and salamanders begin life as gilled, aquatic larvae. In the case of the newt, it leaves the water after two to five months as an orange-red amphibian with black spots down its side. Unlike most salamanders, the eft's skin is dry and rough.
As the red eft matures, its color changes to brown or green, though the red spots down its side remain. Though the mature newt prefers to live permanently in water, it can live on land if the pond or stream dries up. However, it will travel to find another body of water.
There are some newts that don't become red efts and simply mature into adults. Others retain their larval gills, though they are mature animals and can reproduce. Other newts remain at the red eft stage though they can also reproduce.