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ReptilesThe animal class Reptilium includes snakes, lizards, crocodilians, chelonians (tortoises and turtles) and the now extinct dinosaurs. Reptiles evolved around 340 million years ago (mya) and dominated the world from approximately 210-65mya (Jurassic and Cretaceous periods) when most of them were mysteriously wiped out. There are around 6,500 species of reptile alive today. The word reptile comes from the Latin reptare: to creep and repere: to crawl, so really they are creepy crawlies! Reptiles have a hard shell, tough leathery skin or scales made from keratin; the same thing feathers, hair, nails and horns are made from. This reduces the loss of water from inside their bodies on land and protects them from predators. It allows them to live on land and in dry environments. There are many internal physical differences between reptiles and the more primitive amphibians but generally the most important is better-developed lungs. Modern reptiles are all ectothermic (cold blooded) and use their behaviour to control their body temperature, e.g. basking and finding shade. The reptiles are one of the key animal groups to evolve in the history of the planet. An almost complete fossil record shows the evolution of reptiles from amphibians. A less complete record shows the evolution of birds and mammals from warm-blooded reptiles. The key to their success is the completion of their life cycle on land. Reptiles lay eggs with hard shells that prevent them from drying out; the young develop inside the egg and do not metamorphose after hatching. This means that they do not need water to reproduce. Some reptiles give birth to live young by holding the fertilised eggs internally until they hatch so this is not the same as in mammals. Orders (types) of reptile alive today:
Chelonia: turtles, tortoises and terrapins Reptiles available for adoption: Sorry, there are no Green Iguanas available to adopt., Sorry, there are no Burmese or rock pythons available to adopt. |
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