" Rats, the only creatures that seemed to flourish in the trenches, were quite brave and were often a foot long (not including the tail), the size of a small cat. They grew fat on the corpses in No Man’s Land and were known to bite sleeping soldiers’ faces and gather around the eating areas. The French left the rats alone. Like a canary in a coal mine, the rats were a warning that gas shells had been fired. At the slightest whiff of gas, the large rats flipped feet up, dead. The Americans hated them too much to leave them alone. They bludgeoned the rats with shovels and rifle butts or shot them with their side arms. "

― , Courage: Roy Blanchard's Journey in America's Forgotten War