JF Ptak Science Books Post 1822
A fascinating aspect in modern technology and warfare is the reliance upon pigeons and dogs–and their achievements–for war services. Evidently several hundred thousand pigeons were used to relay messages between divisional headquarters and battlefield positions and such during WWI, with something like 90% of the messages being delivered successfully–a remarkable achievement, since it was not uncommon for the pigeons to fly dozens of miles to perform their task. The services worked so well in fact that the American carrier pigeon service training facility for the army was not closed until 1957.
Dogs were used as guards and ambulance litter carriers, but it seems they were mostly used for communication purposes, taking messages back and forth through the masses and intricacies of trenches.
The image below comes from The Illustrated London News for 2 October 1915:
