The totally harmless Ctenosaur (unless you're a flower or a piece of fruit) (c) Richard Brown
The Ctenosaur has a nifty trick to help manage their temperature. Pigment granules can move within individual skin cells to change their colour. So they can be dark on a morning to warm up and more reflective during the hot midday period. Smaller Ctenosaurs may also use changes in skin colour to help with camouflage as there are plenty of Snakes and Hawks which would make a meal of them.