 The order Caudata ( from the Latin cauda meaning " tail " ) consists of the salamanders — elongated , low @-@ slung animals that mostly resemble lizards in form . This is a symplesiomorphic trait and they are no more closely related to lizards than they are to mammals . Salamanders lack claws , have scale @-@ free skins , either smooth or covered with tubercles , and tails that are usually flattened from side to side and often finned . They range in size from the Chinese giant salamander ( Andrias davidianus ) , which has been reported to grow to a length of 1 @.@ 8 metres ( 5 ft 11 in ) , to the diminutive <unk> <unk> from Mexico which seldom exceeds 20 mm ( 0 @.@ 8 in ) in length . Salamanders have a mostly Laurasian distribution , being present in much of the Holarctic region of the northern hemisphere . The family Plethodontidae is also found in Central America and South America north of the Amazon basin ; South America was apparently invaded from Central America by about the start of the Miocene , 23 million years ago . Urodela is a name sometimes used for all the extant species of salamanders . Members of several salamander families have become paedomorphic and either fail to complete their metamorphosis or retain some larval characteristics as adults . Most salamanders are under 15 cm ( 6 in ) long . They may be terrestrial or aquatic and many spend part of the year in each habitat . When on land , they mostly spend the day hidden under stones or logs or in dense vegetation , emerging in the evening and night to forage for worms , insects and other invertebrates . 
