The European Green Lizard, Lacerta viridis, shows off a blue head while catching some rays. Lizards and other so-called "cold-blooded" animals have complex biochemistry: sometimes they have 4 to 10 different enzyme systems where humans would use only 1. Cold-blooded critters need this complexity so that their bodies function no matter how hot or cold they are.
Photographer Dietmar Nill caught the lizard in the Rhodope Mountains on mission to photograph the birds and bats of Bulgaria.
Photo credit: Wild Wonders of Europe