Thanks to the Press Officer at London Zoo allowing access with less than 24 hours notice, one of the most rewarding series of shots with the borrowed thermal imaging camera, happened on the day before it was due to be returned, on a cold, drizzly 3 January 2007.
Several of the images later made it to the national national newspapers and are now in demand internationally. Amateur Photographer magazine wanted to do a feature on the piece and so, with support from FLIR Systems and the zoo, another day of shooting took place on a very warm and sunny 27 May. Amateur Photographer's feature should be ready in July. 

The May images are not so good as January's as the ambient heat was closer to the animals' in the outdoor compounds. As can be seen in the giraffe picture to the right, the heat of the sun had warmed the outside up so much that hard surfaces had become quite hot. 

In the gorilla compound, the chief male sat in a cool cave whilst his subordinates had to make do with the outside. Notice the red (hot) and white (hotter) on the two subordinate gorillas, whilst the big male languished in the cool (dark blue though to black) of the cave  that, had he been generous enough, would have had room for three.

Note the red (hot) and white (hotter) heat detected on the subordinate gorillas and the relative lack of these colors on the mainly yellow (warm) and green (cooler) chief.
Here is a sample of the base images captured. This 'base image set', like all others, is still being reviewed and worked on, as there are so many different ways to manipulate them.

Each original image has, within it, details of the average temperature identified for each pixel. The temperature range that is visually represented can be changed in various ways and an appropriate temperature-color scale can be added when needed. 

The original thermal images can also be stitched together and cropped.  Experiments are ongoing and various examples of work on the original animal pictures will soon be on the Experiments page. More images will be added to this page soon.

These first four butterfly pictures, show how one original thermal image can be reinterpreted though different heat-color spectrums of the same temperature range. 

The respective heat spectra used are: 'Greyscale' (black=cold, white=hot); 'IronScale' (black=cold, through purple, red, and yellow to white=hot); 'RainbowHC' (black=cold, through purple, blue, green, yellow, brown, and red to white=hot, where the infra-red processor has added a hard edge to each area of defined average temperature) and finally, 'Rainbow' (black=cold, through dark blue, light blue, green, yellow and then red to white=hot)

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On the left is an enlarged crop of a butterfly picture along with an appropriate temperature scale. What is interesting is the fact that the butterfly's abdomen looks hotter than its thorax. This seems odd as one would guess that its heavily worked wing muscles would make the thorax hotter. Perhaps a butterfly anatomist might offer an explanation.

Heat from delicate butterfly veins can be seen in the picture to the top right. Other heat sources can also be seen on this yellow-warm table top in the Zoo's butterfly house, but what are they?
To the bottom right is a normal picture taken at roughly the same time. Can you identify all the heat sources? Notice also that, virtually unseen in the visual picture, is a drop of water just below the big butterfly's wing. Cooled by evaporation this shows up as an additional green circle in the thermal image.

Often, a thermal image can be more colorful than a real image, as can be seen in the comparison of real to thermal images of sacred ibis (left) and penguins (below and right). The penguins' camouflage probably helps protect them in the real world, from seals waiting offshore to ambush them.

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South African black footed penguins trundle round the edge of their cold pool in Winter. The young seem to have better insulation.
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The dark stripes on these zebra show up as warmer than the white areas. Why?
This is not because they absorb heat instead of reflecting it, but to do with what is referred to as the 'black-body radiation' effect, which is explained on the About the technology page.

Below, Asian short-clawed otters can be seen to lose significant heat as they shed water leaving their pool, and it is evident that the coolest part of the Mexican red kneed, bird eating spider, is the tips of its legs.
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Clockwise, from top left, these images focus on dealing with the cold. Remember to check each thermal image's unique temperature - to color - scale. See how, in winter, the llama's thick fur traps its body heat. 

The flamingos' feathers perform a similar trick and they even seem to slow the blood to one of their legs to prevent further heat loss.

The camels have a thick winter coat on top, but by late May this has largely fallen off (bottom left) so that they can instead enjoy the heat of the sun.

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The minimum temperature in the thermal picture of a sloth is a balmy 22.2 degrees centigrade, before the color turns to a uniform dark blue. The maximum, before the color turns white is a stifling 31.4 degrees. 

The sloth and its friends, such as the marmosets to the right, like it hot and their habitat is a great place for zoo visitors to get out of the cold on a bleak winter's day.

The pelicans just have to put up with the cold by relying upon their feathers. They even leave warm footprints when they walk.

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To acknowledge a feature in Amateur Photographer in July, some shots of London Zoo's three gorillas, taken on a very hot day in May

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Can you guess what these last few animal pictures are of?

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Try looking on the London Zoo website or even their entry in in Wikipedia

The current image collection on this page will be slowly revised over the coming months. Contributions are invited from anybody who thinks they might have an image of interest. Any third party images and comments used will be marked and hyperlinked as requested. Please see the About page for details of how to contact

Copyright for all images and text resides with Steve Lowe/ Thermalcities, except where otherwise stated.


 Copyright 2008. All rights reserved