Trous de loup might be found singly as a trap (in which case they were always concealed), or in a dense pattern with no gaps between pits, used as an obstacle in front of a defended position. A field of trous de loup could be made most effective if subsequently flooded to a shallow depth, which would conceal the pits, make their sides slippery, and add the risk of drowning. Sometimes rotting meat or feces would be smeared onto the points to cause serious infection and quite often death.