During World War II the U.S. military needed a few good dogs. Actually, the military needed thousands of very good dogs. The U.S. Army and Coast Guard recruited many canines through a New York City organization called Dogs for Defense (DFD). DFD members were patriotic civilian dog lovers ready to enlist their pets for wartime service. Great Britain, France, Russia, Germany. and Japan had been breeding and training dogs in war duties for many years. Germany and Japan—enemies of the Allies during the war—were believed to have canine armies totaling at least 150,000 dogs.

In the 1940s about twelve million dogs lived in the United States. Many of their owners filled out official enrollment applications to see if their dogs would be accepted for military service. The application required the owner's signature and the dog's paw print. The Coast Guard accepted only German...