Woodpeckers are famous for their wood-chiseling beaks, but they are also equipped with an amazing tongue. Woodpeckers peck into tree bark or the wood of dead trees to get at insects living in the wood. Once the woodpecker has excavated a hole in the wood, they need to get the insect or grub out. They use their remarkable tongues to do this.
Their tongues are long and sensitive, which helps them to probe and detect insects in wood. The back of the tongue is attached to a strong, muscular sheath, connected to complex of long bones called the hyoid. The hyoid wraps around the back of the woodpeckers' skull and over the top, creating a mechanism - like the spring of a retractable tape measure - that enables the woodpecker's tongue to extend several inches beyond the tip of the beak. Some woodpeckers' tongues are essentially as four times as long as their beaks.
The tip of the tongue is sharp and barbed, like a tiny harpoon, and their saliva contains a gluey mucus that helps the tongue act like fly paper. Once that sensitive tongue encounters a grub in the wood, it's impaled and stuck to the tongue, enabling the woodpecker to pull it back out.