The geckos constitute the largest family of lizards after the skinks, with about 700-800 species (numbers differ according to source). They are found virtually everywhere on the planet except the polar regions, and have proved successful stowaways and rafters, having been transported along with man to places often far from their point of origin. Part of their success is doubtlessly due to their generally small size: the largest is only 14", while the mean size is about 6-8" and some species are even half or less than that in length.
Apart from their small size, geckos are also invariably characterised by their soft skin, which instead of the hard overlapping scales of most lizards is usually covered to a greater or lesser degree in tubercles. The tails of geckos tend also to be soft and often rather round or fat, as they tend to store reserves of fat and vital nutrients in them. In many species these tails are often dropped and regenerated. Gecko feet are often adapted for climbing up vertical surfaces and even across ceilings, thanks to a system of minute lamellae, or hair-like structures, which find the microscopic imperfections in a surface, even glass, and lodge in it. Most geckos also possess small claws. Most geckos lack eyelids and have a brille over the eye instead, which is shed in the same way as a snake's eye covering when the rest of the skin is discarded. Apart from the obvious Day Geckos, nearly all geckos are nocturnal by nature. Virtually all are insectivorous feeders.
Eublepharid Geckos - "Eyelid" Geckos - including Leopard- and Fat-Tailed Geckos
Gekkoninae: "Typical" geckos - Tokays, Mediterranean- and House Geckos, and many more
Sphaerodactyline Geckos - the diminutive New World geckos. Most authorities now consider these to be a part of the Gekkoninae instead.
Diplodactyline Geckos - the unusual geckos of Australia, New Zealand and New Caledonia.
The Global Gecko Association has a well-organised website with care sheets, captive care information and photographs. They also promote conservation, study in the wild and academic research, and members receive a twice-yearly journal as well as regular newsletters.
Another outstanding gecko site is www.uroplatus.com, run by Boris Klusmeyer. Apart from taxonomic news, literature sources and the like, Boris has an outstanding collection of gecko photographs. Please ask him before you use any, though
Friedrich-Wilhelm Henkel's www.nephurus.org is another good German site and subtitled, "Everything you ever wanted to know about geckos".
Vivarium Herpetoculture specialise in the captive care and breeding of the lesser-known Australian geckos and have some excellent pictures. Expect their website to be expanded soon.
The German site Repti-Box has a very useful summary table of information about many species of gecko contained in these pages.
Index of Gecko-related articles from herpetological magazines
For a fascinating insight into geckos' "adhesive" feet and some scientific observations made on them, go to the very interesting Science & Technology News Network article.