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 six the sand lizard.

This is the final member of British reptile, although some others have been introduced and i will be talking about these in  a later blog. Male sand lizards are probably at their most vibrant with  a bright green flare of scales on the flanks. Accompanying this colour change they become extremely territorial and the presence of other lizards can trigger all sorts of surprising reactions. More heavily built than the common lizard, the sand lizard has two light stripes, sometimes broken, along their back with dark spots between the stripes. Some of the dark spots have pale centres. The male is a greenish colour and the female is a brownish colour, They are both about seven inches in length including their tail. Dry, open country is the home of the sand lizard, mainly the sandy heaths of Hampshire,surrey and dorset. Although there is a small colony living on coastal dunes near Liverpool. The sand lizards population has struggled in recent years as their habitat has given way to farming and forestry. The heath habitat that they live in has to be continually managed to stop trees coning through and the heath reverting back to a woodland habitat. In some areas livestock may be used or deers mat perform the same role to manage the habitat. The sand lizard emerges from its hibernating burrow in march or early April. They may be seen taking in solar radiation in the early hours of the morning. Males normally emerge first, Their winter coat will soon be shed for their new spring breeding colours so they can attract females. In April and may the males will fight for territories and dominance, One adult male may display its flank to intimidate an opponent. The victors will earn the right to then mate with the emerging females, who will show her aggression by opening her mouth and raising and shaking her forefeet alternately, Only mating when she is ready. The male then chases the female before mating and grips her first by the tail, then further forward and finally by the middle of the back. After mating the female then digs a hole in late may or early June. The hole will be dug in a sunny place, Where the sand is soft, then lays her eggs and covers them up. The oval shaped eggs, about half an inch long, hatch after two or three months in late July or early August. The newly hatched are just like the adult lizards but are only about two and a half inches long, they grow rapidly before they hibernate as well at the same time as the adults. The young sand lizards can be distinguished from common lizards by their more conspicuous spots. Beetles,spiders and grasshoppers are their main food, they are often dismembered before being eaten, they feed well during summer to build up reserves in readies for hibernation in late Autumn or early Winter. Sand lizards take about two years to reach maturity, they may live upto about seven or eight years in the wild if they escape the snakes,rats or birds of prey that all prey on them.