Tail shape, length and texture were recorded from 28 species of varanid lizards as well as several other reptiles that were known to be either semi-aquatic or arboreal. The varanids were described with respect to their tail characteristics and we then looked for relationships between tail characteristics and what is known about the habitats and lifestyles of the species. Semi-aquatic species of all sizes and phylogenetic groups have laterally compressed tails with a tall "fin" comprising the dorsal one-third of the tail. The tails of the large non-aquatic varanids are laterally compressed with a coarse texture. The smaller species in the subgenus Odatria have more diverse tails, and the tail characteristics generally correspond to habitats and lifestyles. The terrestrial species that live under rocks on the soil surface have very coarse, spinous tails. Saxicolous Odatria have long, smooth tails, and arboreal species have coarse tails.