FROM CANARIES TO CAMELS
The smallest animals involved in World War One were canaries. These cute little birds were used to cheer soldiers up in hospitals, but also to warn of gas attacks. That's because they're more sensitive to toxins in the air than humans are. The reason is that air only flows in one direction through birds' lungs, so even more fresh air is passing through their lungs when they're breathing out (until as recently as 1986, canaries were used by miners in the UK to warn when conditions were unsafe underground). Pigeons were the most common bird in the war, on both sides, as they could be used to carry messages.
Other common pets in WW1 included cats and dogs. Cats were kept as companions, but they were also useful for keeping trenches free of rats and mice, which can spread disease. For the same reason, lots of navy boats also had a ship's cat.
Dogs did a surprising number of jobs, including helping to set up communication wires, carrying messages or small items, and dragging sleds or gun carriages (top left).
Carrying heavy equipment was a job for donkeys, as well as oxen and camels in some places. Camels were also used to carry injured soldiers to hospital, as well as to take men and equipment into battle. One famous group of soldiers that used camels was the Imperial Camel Corps, which was made up of troops from Australia, New Zealand and Britain, along with others from India, Hong Kong and Singapore. The unit was formed in 1916 to fight Arab and Berber tribes on the LibyanEgyptian border, after they had attacked British and Egyptian outposts.
The troops didn't fight while on the camels, like traditional cavalry units, but used the camels as transport before they dismounted and attacked on foot.
Soldiers on camels use a break in the fighting to pose for a pic