Remarkable Tongue Length
Woodpeckers possess a tongue of surprising length, often extending far beyond the tip of their beak. While the exact length varies by species, a woodpecker’s tongue can be several times longer than its beak, and in some cases, even longer than its head. For instance, the tongue of a Northern Flicker can extend up to 10 to 12 centimeters (about 4 to 5 inches) beyond its beak, which is an extraordinary reach for a bird of its size. This remarkable extension allows them to access food sources deep within tree cavities and crevices. The tongue’s exceptional length is a key feature that enables their specialized feeding habits.
The Hyoid Apparatus: An Anatomical Wonder
The secret to accommodating such a long tongue within a woodpecker’s relatively small skull lies in a unique anatomical structure called the hyoid apparatus. This specialized bone, along with its associated muscles and cartilage, is exceptionally elongated and flexible. Instead of ending at the base of the skull, the hyoid bone wraps around the back and top of the woodpecker’s head. This path often goes over the cranium, sometimes even extending into the nasal cavity or around an eye socket.
This intricate looping of the hyoid bone allows the tongue to be stored compactly when not in use. When the woodpecker needs to extend its tongue, muscles contract, pulling the hyoid apparatus forward and out of the skull. The elasticity of the tongue and the surrounding tissues then permits its rapid projection.
Specialized Feeding Mechanisms
The woodpecker’s long, extensible tongue is a highly specialized tool for extracting prey from challenging locations. Many species have tongues that are barbed at the tip, featuring small, backward-pointing bristles. These barbs help to impale and secure insects, such as beetle larvae, from deep within wood tunnels.
Other woodpecker species, like the Northern Flicker, have tongues covered in a sticky, saliva-like substance. This adhesive coating allows them to pick up ants and other small insects by adhesion, effectively sweeping them from surfaces or out of crevices. The combination of length, barbs, or stickiness makes the tongue incredibly efficient for capturing the specific prey items that form their diet.
Diverse Tongue Adaptations Across Species
While the general principle of a long, extensible tongue applies, there are variations in tongue structure and function across different woodpecker species. For instance, sapsuckers, which primarily feed on tree sap, have tongues that are shorter and brush-tipped. This brush-like tip helps them to lap up sap effectively from the holes they drill in trees.
In contrast, species like the acorn woodpecker, which store acorns in tree holes, have less specialized tongues as their diet is not solely dependent on extracting insects from wood. These variations highlight how the tongue’s morphology is finely tuned to the specific dietary niche of each woodpecker species.