The life of a soldier in the trench’s during WWI was an unimaginable nightmare. If a soldier were fortunate enough to avoid being killed by the enemy, the diseases festering in the puddles at the bottom of the trenches surely would. Furthermore, the moist, dismal, and filthy environment was ideal for rats that would transport and disseminate diseases.

It would have been impossible to place and maintain rat traps in the trench systems that ran along the Western Front of WWI. Instead, an estimated 500,000 cats were used to cull the rodent population. Many soldiers found themselves caring for the cats, sharing parts of their rations with their furry companions, who would muster around troops' living quarters, giving them something to play with between conflicts. The little rat catchers were also adopted as mascots by troops, and were known to be fiercely loyal to the men with whom they served. On cold nights, the cats could be found cozying up on the shoulders of the troops. This sometimes led to upheavals, on one occasion the cat's purring woke the sleeping soldier who thought the loud purring was the buzzing of an enemy aeroplane. Lieutenant Lekeux of the 3rd Regiment of Artillery, a Belgian officer and scout, came across a litter of kittens whose mother had died before they had a chance to open their eyes. The Lieutenant did everything in his power to help the kittens, but only one survived. He decided to name the cat Pitoutchi. Lt. Lekeux had a faithful friend in little Pitoutchi, who would follow him everywhere and jump on his shoulders whenever the trenches were too wet. One night, as Lekeux scouted the German position and put its location on a map, German troops almost spotted him. The troops, alerted by a suspicious noise, quickly surrounded the artillery crater where Lekeux had taken cover. He was trapped. Suddenly, Pitoutchi who had been hiding on Lt. Lekeux's shoulder, jumped off and dashed out of cover. The enemy spotted the little kitten and opened fire, but his cat's reflexes proved too quick for them; the Germans attributed the noise they heard to Pitoutchi and gave up searching. Lekeux used this opportunity to escape, taking the maps and Pitouchi with him.

The cats also freely crossed the unoccupied territory between the trenches, and during the famous Christmas Truce of 1914, soldiers would tie messages around the collars of some free-roaming kitties, and the message would get across to the enemy lines. Sadly, not everyone thought such communication should be taken lightly. One cat by the name of Felix was caught by French officers and put on trial. Felix, who was only trying to carry messages of peace and love in exchange for treats, was found guilty of treason and executed by firing squad.

The trench cats were also very sensitive to the almost odourless and almost invisible toxic gas used against the Allies. This means that the effects of the gas attacks would be almost immediately felt by cats. The reaction of the cats to the gas would be similar to canaries in mine shafts, alerting nearby troops and giving them time to put on their equipment and get to safety.

It is impossible to determine how many cats died in the trenches, on ships or even in the air during World War I, but their selfless actions undoubtedly saved countless lives.