Woodpeckers have unusually long tongues, a unique adaptation that helps them thrive in their ecological niche. This feature allows them to access food sources other birds cannot.
Specialized Feeding Strategy
Woodpeckers forage by drilling into trees. Their diet primarily consists of insects and larvae, such as wood-boring insects, grubs, and ants, found deep within wood or beneath bark. They use strong, chisel-shaped beaks to excavate holes, then retrieve prey from these deep spaces.
Certain woodpecker species, like sapsuckers, have a specialized diet that includes tree sap. They create rows of small, shallow holes in tree bark, known as “sapsucker wells,” to allow sap to flow. This sweet liquid attracts various insects, which sapsuckers also consume. The long tongue is essential for reaching both the sap and the insects. This ability to extract otherwise inaccessible food items drove the evolution of their unique tongue.
The Tongue’s Remarkable Anatomy
The woodpecker’s tongue is adapted for foraging, with exceptional length. In some species, it can extend up to 5 inches beyond the bill or be nearly twice the beak’s length. This length allows the bird to probe deep into crevices and holes.
Other adaptations enhance its function. The tip of many woodpecker tongues is covered in tiny barbs or bristles to secure prey. Additionally, the tongue is coated with a specialized sticky saliva. This adhesive quality helps the woodpecker snag and hold onto slippery insects and larvae. For sapsuckers, the tongue may have a brush-like tip, allowing them to lap up tree sap.
Supporting Structures and Mechanisms
The tongue’s length and function are supported by the hyoid apparatus, a complex anatomical structure. This system of bones, muscles, and cartilage differs from the hyoid bone in most other birds. In woodpeckers, the hyoid apparatus is elongated, with horns wrapping around the skull.
It typically anchors near the nostril or eye, extending over the skull and around the back, sometimes coiling behind the brain before connecting to the tongue. Muscles surrounding the hyoid contract, propelling the tongue forward for extension. This arrangement stores the long tongue and stabilizes the skull during high-impact pecking. The hyoid apparatus, with other cranial adaptations, helps absorb drilling forces, protecting the woodpecker’s brain.