Why snakes and lizards bask in the sun.

Although reptiles such as snakes and lizards are usually described as cold-blooded,they spend much of their lives with their bodies nearly as warm as in a warm-blooded animal. What they lack is a means of producing and maintaining their own body heat. To reach a body temperature at which muscles, senses and digestion are fully active (about 77-90f and 25-32c), they have to rely on outside heat-either conducted from their surroundings or, more often, direct from the sun`s rays. In Britain, reptiles are dormant in winter because they cannot reach their working temperatures. In spring they emerge on sunny days, but the sunshine is so weak they need to bask almost all of the time.  As the sun gets stronger, basking time is shorter-mainly early and late in the day- and there is time for hunting and breeding. By midsummer basking is hardly necessary, but as autumn comes the need increases, and finally the animals are forced into hibernation. Reptile species that bear live young can usually survive in cooler climates than those that lay eggs, by basking during pregnancy, they can get enough heat to ensure faster development of the young but warmth cannot ensured for the eggs. This is one reason why the adder and the common lizard, which bear live young, can live further north than the grass snake and sand lizard, which lay eggs.

British reptiles.

Part four the common lizard.

The common lizard is found throughout the British isles and may live upto six years. Common lizards can be found in various habitats, Heathland, Sand dunes, and grass or grass covered banks are some of the best places to find them. They emerge from hibernation in early spring and might be seen taking in solar radiation on early mornings. Common lizards mate in April with some wonderful courtships with the male trying to impress the female. Then up to eight young are born in midsummer. The young are born fully formed, each in a transparent capsule that usually breaks at birth, They may be born together at once or over a one or two day period.Common lizard have a varied diet which includes harvestman,flies,beetles,caterpillars and spiders which they may hunt during warm summer days. They will pounce on their prey, shake it to stun their prey, they then swallow it whole.  Common lizards may be predated themselves by smooth snakes,adders,rats and kestrels, However if a common lizard is captured it may shed its tail to enable it to escape from its prey. A new tail will regrow but never to its original size. Common lizards are a dull brown in colour with a tinge of red,yellow,green or grey with a dark back stripe, They also have dark side stripes. The female is normally fatter than the male and about six inches in length. Common lizards are very agile with very sharp claws which are wide spreading, Enabling them to be great climbers. They have short legs and a tail that is normally longer than their body.The underside of the male is orange with black spots, The female has a lemon-yellow colour underside with no spots. Lizards have rows of scales across their underside unlike snakes who have single scales. The transparent surface layer of is shed periodically. It is scraped off in pieces, making the lizard look ragged until all of the skin has come off. Common lizards can spend all of their lives on land unlike newts who go back to water to breed. Common lizards are viviparous like adders, They keep their eggs inside their body until they are ready to hatch. They have fantastic smell and sight senses.