Skinks are lizards belonging to the family Scincidae. Together with several other lizard families, including Lacertidae (the “true” or wall lizards), they comprise the superfamily or infraorderScincomorpha. With about 1200 described species, the Scincidae are the second most diverse family of lizards, exceeded only by the Gekkonidae (or geckos).
Skinks look roughly like true lizards, but most species have no pronounced neck and their legs are relatively small; in fact several genera (e.g., Typhlosaurus) have no limbs at all. Some other genera, such as Neoseps, have reduced limbs, lacking forelegs, and with fewer than five toes (digits) on each foot. In such species, their locomotion resembles that of snakes more than that of lizards with well-developed limbs. As a general rule, the longer the digits, the more arboreal the species is likely to be. A biological ratio exists that can determine the ecological niche of a given skink species. The SENI (Scincidae Ecological Niche Index) is a ratio based on anterior foot length at the junction of the ulna/radius-carpal bones to the longest digit divided by the snout-to-vent length (SVL).
Most species of skinks have long, tapering tails that they can shed if a predator grabs the tail. Such species generally can regenerate the lost part of a tail, though imperfectly. Species with stumpy tails have no special regenerative abilities.
Some species of skink are quite small; Scincellalateralis typically ranges from 3 to 5.5 inches (7.5 to 14.5 cm), more than half of which is tail. Most skinks however, are medium sized with snout-to-vent lengths of about 12 cm (4 or 5 in), although some grow larger; the Solomon Islands skink, (Coruciazebrata), is the largest known extant species and may attain a snout-to-vent length of some 35 cm (13 to 14 in).