The lizard is a temperature-changeable vertebrate animal

The answer is: reptiles.

Lizard is a temperature-changing vertebrate animal belonging to the group of reptiles. It resembles a snake in that it has no legs. Reptiles are thermophilic animals, which means they are adapted to warm climates and temperatures. Lizards, snakes, turtles and chameleons belong to this group of reptiles. They can be distinguished by their need for external heat sources such as the sun or warm rocks to maintain optimal body temperature. The lizard is a unique animal because it is able to change its temperature using both physical and behavioral means. Physically, it can adjust its color to better absorb or reflect heat. Behaviorally, they can also seek out warm spots and regulate their activity levels based on the temperature outside. This gives the lizard an incredible ability to survive in a wide range of habitats.