The tongue of a woodpecker is up to 4 inches long and three times the length of its bill. The length and structure of a woodpecker’s tongue varies by species, diet and foraging method.
Species that peck wood to extract insect larvae, such as downy woodpeckers and pileated woodpeckers, have shorter tongues with backward-facing barbs. Species that use their tongues to dislodge insects from crevices in tree trunks have longer tongues with barbs concentrated at the tip. The woodpecker’s barbed tongue also has sublingual salivary glands, which produce sticky saliva that helps the bird to catch insects. When the long tongue is not in use, the woodpecker wraps it around the back of its head, between the skull and the skin.