They're good to eat in Nethack, unless you are a Monk. Bands have been named after them, and a peninsula in Britain bears their name, without actually being named after them. But what are the damn things?
A lizard is an animal that belongs to the suborder Lacertilia (or Sauria -- the two are synonymous), within the order Squamata in the class Reptilia. That's a whole lot of Latin, but bear with me, herpetology types tend to dig that sort of thing. They have a secret herpetologist world conspiracy, and communicate their plots for total world domination in Latin. Meanwhile, I'll try to explain what it means to the rest of us:
Reptilia, in case you haven't guessed, is the class of reptiles. Basically put, an animal belongs to this class if it is a vertebrate (ruling out insects, mollusks, crustaceans and similar creatures), breathes using lungs (ruling out fish), does not undergo a larval stage (ruling out amphibians) and is exothermic (ruling out mammals and birds). Exothermic? In normal English, that trait is usually called being "cold-blooded", but this is in fact a misnomer -- a reptile in a very hot environment will have warmer blood than you, the difference is that reptiles do not have any internal heat regulation mechanism, like mammals do. As a side note, this is actually the reason why many reptiles have very long life spans -- they do not burn up lots of energy and wear down their system by doing heat control. It also means that they are very sensitive to the surrounding temperatures, and extreme heat or cold can kill them. Since most regions of the Earth have periods of cold in the winter, most reptiles can hibernate and survive colder weather than otherwise while they're in suspended animation.
Within the class of reptiles, there are four surviving orders (about 16 more are known to have existed, but are long extinct). These are Rhynchocephalia (the tuataras -- amazingly funky creatures, but they're stuff for another node), Chelonia (the turtles and tortoises), Crocodylia (the crocodiles, alligators, gavials and caimans), and Squamata (the scaly reptiles). Scaly reptiles? Aren't all reptiles scaly? Not quite. Tuatara "scales" are not true scales at all (although they look almost like it), chelonians have a hard shell of horn and otherwise soft skin, and crocodilians have large horn armour plates rather than fine scales. This leaves out snakes and lizards, who indeed comprise the Squamata order.
Snakes and lizards differ in several ways: First, lizards are covered in scales on their entire bodies, whereas snakes have broad plates on their underbellies. Lizards have two lungs and two kidneys, snakes only have one of each. Snakes have tiny tails and very long bodies, with lizards it's the other way around. Snakes have transparent eyelids that are always closed (explaining why they're cranky while they're shedding skin), lizards have movable eyelids like humans. Snakes have no legs, and lizards do? Not necessarily. Some lizards are legless (some skinks, as well as the slow-worms), and some pythons have tiny, vestigial remnants of legs. Finally, with a single exception, all lizards have ear organs, while all snakes do not (and, in fact, have no sense of hearing at all).
Why spend so much time explaining what lizards are not? Because it's easiest, really. Lizards are an amazingly varied suborder, easily the most varied suborder of any class of animals on the planet (it is, in fact, the one which has most member species). Except for polar regions and mountain tops, there are lizards adapted to just about any environment on Earth. There are lizards with and without legs, there are lizards that lay eggs and there are a few who bear live young. There are tiny geckos that can sit on a human's thumb, and there's the four-meter-long monster that is the Komodo dragon. Some geckos have well-developed vocal cords, and can sing, like birds. Two species of lizards have venom (the beaded lizard and the gila monster are, contrary to popular belief, the only venomous lizards on Earth). Some have transparent scales (and thus, visible internal organs), others communicate with each other by changing their scale colour. Some lizards are arboreal and live their entire lives in the branches of trees, some are terrestrial, some are subterranean, a few can fly by gliding and a single species (the Marine Iguana) is even seagoing. Some have adapted well to living in the inner city, others are sensitive to even the slightest change in the environment. Some are vegetarians, and some are fierce carnivores. Some can detach their tails and regenerate it (just like the Spider-Man character The Lizard), others can't. Most smell their surroundings using their nostrils, but others use their tongues and a Jacobsen organ like snakes.
If you want to know more about lizards, it's probably best to read up on the particular family of lizards you are interested in. The suborder has the following families:
- Agamidae: The agamas, including water dragons, flying dragons and many lizards exclusive to Asia.
- Amphisbaenidae: The worm lizards, also known as slow-worms, found on both sides of the Atlantic.
- Anguidae: The alligator lizards and glass snakes, these live in the Americas.
- Anniellidae: The legless lizards, this family consists of two species, both American. They're not the only lizards without legs, though.
- Chamaeleonidae: The chameleons, everyone's favourite colour-changing insectivore, nature's very own pest exterminator. There are a few European species, but most chameleons live in Africa.
- Gekkonidae: The geckos. Master climbers, these lizards can climb glass. Some of them can sing, too. Others of them make noises that can only be called "singing" if you are into some seriously twisted music. They are spread throughout the world.
- Helodermatidae: The venomous lizards. Comprising only two species, this family lives in America.
- Iguanidae: The iguanas. Ranging from the very large green iguana (or common iguana) and the even larger marine iguana of the Galapagos to the tiny anoles, this is a very varied family of lizards that primarily lives in the Americas, except for a few Australian species.
- Lacertidae: The common lizards -- these are mainly found in Europe. There's no such thing as a common lizard, though, I guess they have the name because Europeans were the first to go around classifying animals, way back when.
- Lanthanotidae: The earless monitors, an elusive family of large lizards consisting of only a single species. They live deep underground, and may be the missing link between lizards and snakes.
- Scincidae: The skinks. These are probably the most varied family, having both legged and legless, herbivorous and carnivorous, egg-laying and live-bearing members. Skinks are spread throughout the world.
- Teiidae: Including species such as the whiptail lizards and caiman lizards, this family lives in the Americas.
- Varanidae: The monitor lizards. Very large lizards that live primarily in Africa and Australia. The Komodo Dragon, largest of all lizards, belongs to this family.
- Xantusidae: The night lizards. Not the only nocturnal lizards, this family of tiny insectivores is exclusive to the Americas. The largest member of the family, the desert night lizard, grows to the majestic size of 5 centimeters.
There you go. Now go play Nethack and try to identify the species of those you eat.