The nearly 6,000 lizard species have adapted to their environment in nearly as many ways. Some evolve camouflage that helps them to blend in with their environment, while others develop gaudy colors and displays used to attract the attention of mates or to dissuade competitors. Lizards frequently adapt to the food sources available in their habitats as well as the predators from which they must hide.
Lizards also evolve different sizes and shapes to adapt to their habitat. For example, lizards living on islands without large predators often evolve to very large sizes. By contrast, lizards that live in competitive environments that have relatively little food often evolve to smaller sizes. Those lizards that spend time in the trees often develop strong, dexterous appendages, while those who spend lots of time burrowing usually exhibit reduced limbs. Some species have lost their legs entirely, and resemble snakes in numerous aspects.
Lizards adapt their behavior patterns to their environment as well. Those species living in deserts often adapt to the intense heat by sleeping through the day and becoming active at night, when the temperatures are cooler. Many geckos have managed to survive in highly competitive environments by becoming nocturnal, which give them access to the abundant insects that fly at night.