The scientific name for the Thick-tailed gecko is Underwoodisaurus milii, and they are also referred to barking geckos. They are members of the Gekkonidae-- or Gecko family. Thick-tailed geckos are communal lizards native to Southern Australia. They are terrestrial geckos, or ground dwelling, from varied areas from wet coastal areas, leaf-covered forests, dry woodlands, to arid scrubland consisting of hard-pack sandy soil. They live in sheltered crevices in rocks or under loose bark at bases of trees. Thick-tailed geckos are "nocturnal," hunting for food at night, and are generally less active during the day.