Lizards are part of a group known as reptiles. There are over 4000 species of lizards. Most lizards live on land but some will make their homes in the water or trees. You have many shapes and sizes along with a wide variety of diets. Some eat just plant matter, while others eat both plant matter and insects and, of course, there are some who only eat meat. Lizards depend on the sun for a healthy existence. The life span of some lizards is 50 years.