New thermal images of animals at London Zoo highlight how they distribute heat and could be used to keep them well.
The images, taken by zoo visitor Steve Lowe, demonstrate how they regulate their own body temperature.
They highlight the difference in heat between Zebra stripes and pelicans can be seen with hot feet.
Zoological director David Field says such pictures can also be used in veterinary diagnostics "as infected areas sometimes appear very hot".
The sacred ibis cutting off the blood supply to one leg to conserve energy is revealed in the images as well as the warm veins running through a butterfly's wings, the sloth's cold nose and the insulating nature of a lion's mane.
Mr Lowe donated the photos to the zoo, to use as part of its education work.