Visitor Steve Lowe used a thermal imaging camera to take a series of photos of birds, animals and insects at London Zoo.
The pictures reveal the heat emitted by the creatures' bodies, showing how effectively their fur and feathers insulates them. This pelican has left a warm trail of footprints behind him.
The warm veins can clearly be seen through the wings of these butterflies, with the hottest areas shown in white.
Cooler areas are shown in red, yellow, green then blue - as demonstrated by these flamingos, whose beaks are far hotter than the rest of their bodies.
The heat difference between a zebra's stripes is shown, as dark stripes absorb heat while the white areas reflect it. The photos will be used in the zoo's educational work.