Columnist William Safire claimed in the December 15, 2003 New York Times that the term originated in the Vietnam War. According to Safire, one of the characteristics of these holes was that they held a "clay pot large enough to hold a crouching man." If the pot broke, the man was exposed to attack from snakes or spiders, hence the name "spider hole". However, the term is usually understood to be an allusion to the camouflaged hole constructed by the trapdoor spider.
During World War II, spider holes were used by Japanese forces in many Pacific battlefields, including Leyte, the Philippines and Iwo Jima. They appear to have been used chiefly to harass rear formations. Japanese troops in spider holes would often wait for the main advance to pass (sometimes for days on end) before launching their attacks. Some spider holes even contained primitive land mines that the Japanese were supposed to detonate in a suicide attack if a tank or other vehicle rolled over them.
Spider holes were used to considerable effect by Vietcong fighters during the Vietnam War. The guerrillas would position themselves in spider holes between two or more U.S. or allied units. They would open fire on the U.S. troops from their spider holes and then close the lid, disguising the hole. The U.S. troops would return fire in the direction of the guerrillas, inadvertently firing on other American units located in the same direction. They, in turn, would return fire. The guerrillas would thereby draw the U.S. units into a fratricidal firefight, often causing heavy casualties and significantly demoralizing the survivors.
The former Iraqi dictator Saddam Hussein was captured by U.S. troops in Operation Red Dawn on December 13, 2003 (Iraqi Time), after being found hiding in a spider hole in the central Iraqi town of ad-Dawr.