Types of Lizards
Lizards are Reptiles, or members of the class Reptilia, and inhabit all of the continents apart from Antarctica. Lizards live in diverse environments and are the most geographically widespread of the reptiles. That makes them the largest group of reptiles with about 5000 species. They have walked the earth for some 200 million years.
Reptiles have the following physical features: they have vertebrate, lungs, and scales or plates. They are cold-blooded, getting all of their heating from the environment (the sun) which can be deadly during cold spells. What could be good about that? Well, this allows the reptiles to eat much less than a mammal of the same weight might. In the desert, for example, this might be useful in terms of competing for food. Also, since they don't need so much energy from food to heat themselves they can spend more time basking and taking in the sites.
Most lizards are four-legged, but some have only two legs and even a few are leg-less. Lizards size ranges from 2 in to 10 ft in length. There are 2 species that are venomous, the Gila Monster and the Mexican Beaded Lizard.
See more about Chameleons
Some lizards change colors very quickly to match their environment, like the Chameleon. Their colors are also affected by the sun. Often, when basking in the sun, the colors of a lizard's skin can become bright and vibrant like the Collared Lizard. A cold lizard may be dark and colorless.
Distinct colors, aside from simply being interesting, like having a blue tongue, a bright red dewlap, or yellow spots, may help lizards identify each other and even communicate. Lizards have very keen eyesite and they also use body language posturing and gestures such as head-bobbing to communicate with each other.
You may also notice that the Collared Lizard above is shedding a layer of old skin. The skin or scales of a lizard is made up of keatin. This substance is also what human fingernails are made of. Collared lizards are known to be aggresive and they eat other species of lizards.
Unfortunately for lizards, life on the earth populated with humans is not all about good times. Central Americans do like to eat the iguanas and think they taste good, calling them "tree chicken". In Central America, the black iguanas are called garrobos, and the green iguanas are called iguanas, so you might find "sopa de garrobo" or "iguana soup" on some menus. Charbroiled tail of iguana can also be found. The common method of hunting is with a slingshot. Freshly killed prey is often held up for display alongside the highway by the hunters, in order to entice buyers. Another lizard, the Uromastyx or Spiny-tailed lizard, is commonly eaten in many countries from Northern Africa through the Middle East and in India.
Common Iguanas are not bad swimmers. When attacked, an iguana may jump from a tree or rock into the water to swim away.
Marine iguanas live only on the Galapagos Islands and it is thought that they arrived to the islands by floating from mainland South America on debris. They can dive as deep as 50 feet (15m) underwater to feed on algae. They can stay under water for up to 20 minutes. In order to stay down for very long in colder temperature water they have to first heat up their bodies in the sun, slow down their hearts in the water, then re-heat in the sun again once they get out.
Basilisks are great runners. When in danger, these lizards start running upright on their back legs. They can even run fast enough to walk, or run really, on water. This has caused them to be referred to as the "Jesus Christ Lizard".
See more about the Jesus Lizard
The tuatara has virtually remained the same for over 140 million years. The tuatara is a reptile, but not in the lizard family, it is part of the family Rhynchocephalia (which translates to Beakheads) which appeared over 220 million years ago. All the Beakheads, besides the tuatara - 2 species, became extinct about 60 million years ago. They are very rare, nocturnal animals.
Chuckwallas are rock dwellers in the Southwest USA and Mexico. When threatened, they crawl into crevices and puff-up their bodies so that they are tightly wedged in and nothing can yank them out.
Lizards have crude third eyes on top of their heads that senses whether it's day or night.
The "Horned Devil" shoots blood from its eyes to scare away predators.
See more about this Thorny Devil
A flying dragon lizard avoids danger by opening two large, winglike flaps of skin and gliding from tree to tree. The lizard steers and brakes with its tail. The large flaps are supported by elongated ribs which they can expand and retract. The wings are brightly colored and for this reason they are also called the "butterfly lizard".
The Bearded Dragon is one of the most common lizard pets, along with iguanas. They are generally docile.
The Gecko is the only lizard and reptile that speaks or barks. Many species are well known for their specialized toe pads that enable them to climb smooth and vertical surfaces, and even cross indoor ceilings with ease. There are an estimated 2,000 different species of geckos worldwide, with many in existence still yet to be found. Just recently a 100-million-year old gecko species was discovered in the Eastern Himalayas.
One gecko with distinct coloring and bark! - Tokay Gecko
This defensive posture of the frilled lizard is intended to increase its apparent size and intimidate adversaries. They open their frills around their necks and hiss when threatened.
Agamids are lizards of the Old World. There are more than 300 different species in Africa, Asia and Australia. Their counterpart in the Americas would be the Iguanidae. Some agamids enjoy the water and others prefer the trees.
Photo search for "Agamidae" on Flickr.com:
Lizard Book at Amazon.com: