Lizards :: essays research papers

Lizards Lizards belong to the class Reptilian, Scientists have said that Reptiles have been on earth for about 200 million years. Lizards make up the largest group of reptiles with more than 4,300 species around the world varying in different shapes and sizes. Lizards look very similar to salamanders but they differ from each other in many ways such as their dry scaly skin and have clawed feet and external ear opening. The majority of lizard are quite small have 4 legs and have a fragile tail that can regenerate when part of it is taken off. Lizards are cold-blooded or ectoderms, which means that they depend on sources outside their bodies like the sun, to raise and maintain there body temperatures. Eating habits vary for lizards and depend upon the species. Some lizards feed only on insects such as the Iguana. On the other hand some eat rodents that roam deserts and eat eggs and small rodents and some feed on both rodents and insects. For protection many lizards use their teeth to scare pre dators off. Lizards are found in tropical and subtropical regions within the world. Few species of lizards are found in temperate regions and none are located in arctic areas. Some lizards are terrestrial, arboreal, or semi-aquatic. Very few lizards are poisonous and use their venom as a defense. Several other species of lizards don’t have a good defensive strategy and rely on camouflage such as the chameleon that is able to change its color according to its surroundings. Females of most lizard species lay eggs then are usually left to hatch on their own. How ever an insignificant amount give birth to living young such as the slowworm. Some female reptiles, mostly green iguanas, do not need a male of their species to begin their reproductive cycle while others do need the presence of one or more males, and need to stimulate the hormone and other changes that lead to egg maturation and laying. To confuse matters more, some female reptiles, especially chelonians, can retain sperm for many years before finally laying a fertilized egg. Most lizards are harmless and benefit humans by keeping the insect populations stable and halt over population. Some species are a source of food; some are killed for their ski ns, but is not illegal in many countries. A vast number of lizards are threatened by violations on their habitat.