The caterpillars are accordingly called "loopers", "spanworms", or "inchworms" after their characteristic looping gait. The cabbage looper and soybean looper are not inchworms, but caterpillars of a different family. In many species of geometer moths, the inchworms are about long. Many inchworms, when disturbed, stand erect and motionless on their prolegs, increasing the resemblance. Leeches generally use suckers at their front and rear ends to move like inchworms. Certain destructive inchworms are called cankerworms.