Reptiles are cold-blooded animals that are incapable of generating internal body heat. The majority of reptiles live mainly in the water but come ashore to lay their eggs on land.
Anatomy
The external anatomy of the various 7,984 species of reptiles varies immensely. However every reptile has a form of scales. The purpose of the scales is to provide a barrier to protect the reptile from predators, abrasions and insects or parasites. The scales also help the animal to avoid dehydration. The internal skeleton of the reptile is made up of small bones which provide a sturdy frame.
Senses
The reptile’s senses are far more developed than that of amphibians. Some reptiles even have sensory organs that are not found on any other creature in the animal kingdom. Most reptiles have large well-developed eyes, with the exception of a few species including many snakes. The hearing ability of most reptiles however is lacking. Some have no external ear opening or middle ear structure at all. Reptiles do not have a developed sense of taste but their sense of smell is excellent. A few species of snakes have an organ in their face that allows them to detect very small changes in heat, enhancing their ability to find prey.
Temperature Control
Reptiles cannot generate their own internal heat and so they must rely on external factors to control their body temperatures. Most reptiles prefer to be at a temperature between 86 to 104 degrees; any lower and they begin to slow down. Many raise their body temperatures by basking in the sun on a flat surface. In regions that have longer colder months many reptiles will hibernate and wait for warmer weather. In areas that are particularly hot the opposite can occur, with reptiles hibernating through the part of the year that is too hot for them.
Reproduction
The majority of reptiles lay eggs, nearly always on land. There are several species of snakes and lizards that are exceptions and give birth to live young. Most reptiles’ eggs have a leathery covering that allows water and oxygen to pass through to the developing embryo. Depending on the length of gestation and the area the animals live in, many will bury their eggs in sand or under vegetation to keep them safe. Newborn reptiles are always very similar to their parents, although their coloring and markings may be different. Most reptiles receive very little parental care. The only exception is crocodiles who look after their young for up to two years.
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