Physical Characteristics

                        Most salamanders are small and slender with long tails, but range in size from the
                        newts at about 10 cm (4 in) to the giant salamander of China and Japan at about 2
                        m (5 ft). The hellbender (61 cm/24 in) is the largest salamander in the U.S. Most
                        salamanders move around on four legs; a number of species, such as the congo
                        eel, however, have only weak or rudimentary legs, and such species as the siren
                        have only two legs. Like some reptiles, salamanders often have the ability to
                        regenerate lost legs or tails. 

                        Salamanders are generally brightly colored, with smooth moist skin that
                        distinguishes them from lizards, which have dry scaly skin. Salamanders absorb
                        water and breathe through the skin. The skin also secretes mucus to maintain
                        moisture; some species secrete a toxin when frightened. 

                        Behavior

                        Salamanders are somewhat sluggish and shy, feeding mostly at night on worms,
                        slugs, snails, and other small creatures. Most females lay their eggs in water,
                        where the larvae hatch with external gills; the gills usually disappear during
                        metamorphosis, although some, such as the mud puppy, retain their gills after the
                        lungs develop. The mud puppy, the axolotl, and the sirens are unusual in that they
                        attain maturity and reproduce in the larval stage. Axolotls in captivity, however,
                        when stimulated by thyroid extracts, will completely metamorphose into common
                        yellow-spotted brown salamanders. 

                        Habitat

                        Most salamanders are terrestrial, inhabiting water only in their larval state and
                        returning to it only to deposit their eggs. All require moisture, however, and generally
                        live in damp areas in the north temperate zone; they often hibernate in colder
                        regions. Several species are fully aquatic, never leaving the water; some are
                        arboreal, or tree-dwelling; and a few sightless species dwell in caves. 

                        Salamanders are generally harmless to humans, and certain species make
                        excellent pets.