The sand lizard is larger than the common lizard, and somewhat stockier. Sand lizards have an attractive pattern of dark spots with light centres (ocelli), over a background of brown or grey. Males develop vivid green flanks in the breeding season (April to May). Juveniles are a more uniform brown, with distinct ocelli. There is some regional variation in appearance between animals from the north of England and those in the south, which are darker overall. Sand lizards need a variety of structural and temperature conditions to allow them to regulate their body temperature and seek cover from predators. Dense heather and marram grass help to provide this in their typical habitats. A key requirement is for unshaded sand patches, in which to dig burrows for egg-laying and for shelter. Sand lizards are 'ectothermic', which means they are unable to generate their own body heat and need to bask in the sun, or be in contact with warm surfaces, to raise body temperatures. It is often said that lizards are 'cold-blooded' but in fact this is not true: their blood temperature varies with the environmental conditions, and therefore in high summer sand lizards actually have warm blood. They are active in warm temperatures, and the lizards pursue activities such as mating or foraging. Sand lizards retreat to a burrow or other refuges by the time the sunlight fades, and remain inactive during the night. In some conditions they may also remain inactive in burrows during the day, for <b>...</b>