Woodpeckers are unique birds that are instantly recognizable by their sharp, chisel-like beaks and their distinctive pecking behavior as they search for insects hidden in trees. One of the woodpecker’s most fascinating anatomical adaptations is its unusually long tongue, which wraps around its skull when not in use. This extraordinary tongue allows woodpeckers to extract insects and larvae from deep within trees. But why do woodpeckers have such unusually long tongues, and why do they wrap them around their skulls?
Woodpecker Tongue Anatomy
The woodpecker’s tongue is very long, often longer than the length of its entire body. It is spear-tipped and barbed to help impale prey. The tongue originates near the back of the woodpecker’s head, passes through its right nostril, goes over the top of its skull, and then curles underneath before exiting the beak.
When not in use, the woodpecker’s tongue retracts and wraps snugly around the skull, just barely squeezing into a special groove. There it is anchored to the mandible by small muscles and connective tissues. Stored in this compact fashion, the entire tongue lies protected, occupying very little space within the beak.
Why Do Woodpeckers Have Such Long Tongues?
The woodpecker’s extra long tongue allows it to reach deep into holes and crevices within trees, accessing tunnels bored by beetle larvae and other wood-dwelling insects. Their unique tongue functions like a spear, darting in and out to skewer prey items.
Most other bird species have tongues much shorter in proportion to their beak size. But woodpeckers rely on chiseling into and probing solid wood to find food, tasks that require specialized tools.
The woodpecker’s spear-like tongue can extend 2 to 3 times the length of its bill, giving it an impressive reach. Slow-motion analysis shows their tongues can protract and retract at speeds over 7 meters per second, with incredible accuracy. This allows them to seize fast-moving, deep-burrowing insects.
Key Advantages of the Woodpecker Tongue
– Greatly extended reach into tunnels and crevices
– Spear-tipped with backward-facing barbs to hook prey
– Fast protraction/retraction to catch fast-moving insects
– Sticky saliva helps collect and retrieve insects
Why Do Woodpeckers Wrap Their Tongues Around Their Skulls?
When not being used to capture prey, the woodpecker retracts its tongue back into a specialized sheath-like groove that conformingly wraps around its skull. There are several advantages to storing the tongue in this unusual fashion:
Protection
With the tongue wrapped safely around the skull, it is protected from damage while the woodpecker is pecking and chiseling. Hard pecks against wood could potentially harm the tongue if it was loose in the beak cavity.
Space Savings
By tightly wrapping around the skull, the tongue occupies minimal space when retracted. This is important since the woodpecker skull needs ample room for large muscles to control the powerful beak/tongue actions.
Support
The sheath provides a scaffold to brace the tongue on the skull. This allows woodpeckers to protract their tongues with great speed and force without damaging muscles or surrounding tissues.
Isolation
Keeping the tongue isolated in its own separate groove also helps prevent accidental swallowing of wood debris and splinters while the bird is drilling into trees.
Interesting Facts About Woodpecker Tongues
The specialized tongue of woodpeckers is an amazing adaptation. Here are some fascinating facts:
– The bones at the tip of the tongue (called the hyoid apparatus) extend from the throat up through the nostrils to the forehead.
– The tongue starts out as cartilage but gradually ossifies into bone.
– The tongue wraps at least halfway around the skull in a 360-degree spiral.
– The tongue sheath has additional grooves and flanges to match the shape of the tongue.
– Muscles allow the tongue to be extended up to 5 times its resting length.
– Large salivary glands coat the tongue with sticky mucus to help grab and retrieve insects.
– Male and female woodpeckers have differently shaped tongues adapted for their roles. Males excavate holes in trees, so their tongues are more spear-like. Female tongues are more flattened to line nests.
Tongue Function Across Woodpecker Species
There are over 200 species of woodpeckers that occupy forests around the world. While tongue adaptations allow all woodpeckers to probe into wood, there are some slight differences across species and feeding techniques:
Species | Tongue Function |
---|---|
Downy Woodpecker | Shorter tongue for shallower probing |
Pileated Woodpecker | Longer spear-tipped tongue to pry out carpenter ants |
Northern Flicker | Barbed tip and sticky saliva to catch ants and termites |
Lewis’s Woodpecker | Thinner tongue to pick insects off surfaces |
How Do Woodpeckers Use Their Tongues?
Woodpeckers utilize their specialized tongues in clever ways to help extract food from trees:
– Darting Motion – The tongue spears forth in a rapid motion to impale prey against the walls of tunnels and crevices. Slow-motion footage shows the tongue moves with incredible speed and accuracy.
– Barbed Tip – Backward-facing barbs or spines on the end of the tongue help grasp squirming insects and keep them from escaping.
– Sticky Saliva – Copious saliva produced by large glands coats the tongue, allowing it to adhere to slippery larvae and pull them out of tunnels.
– Flicking Action – Once an insect is speared, woodpeckers retract their tongues rapidly, flicking the prey loose into their mouths.
– Persistence – Woodpeckers probe repeatedly with their tongues, lapping up termites and ants deep within nesting chambers.
Unique Adaptations in Woodpecker Skulls
In addition to the unusual tongue, woodpeckers have many other specialized adaptations that allow their unique feeding strategy:
– Nostril Slit – The right nostril is elongated to allow passage of the tongue from the throat to the tip of the beak.
– Sheath Groove – A deep groove and flanges wrap 180 degrees around the skull to cradle and support the tongue.
– Shock Absorption – Thick neck muscles and springy sinuses cushion the brain against the forces from repetitive pecking.
– Reinforced Skull – Compacted bone structure surrounding the skull helps absorb impact and resist breakage.
– Chisel-tipped Beak – Their straight, strong beaks have a reinforced point ideal for drilling and chiseling into wood.
Conclusion
The exceedingly long tongue of woodpeckers is an amazing anatomical adaptation that allows them to extract wood-boring insects, an abundant food source other birds can’t access. They can dart their spear-tipped tongues deep into tiny cracks and crevices with incredible speed and accuracy. When not is use, the tongue wraps snugly around the skull for protection, support, and isolation while the woodpecker is chiseling. Together with reinforced skulls and specialized beaks, the tongue allows woodpeckers to occupy their unique ecological niche. This fascinating tool helps explain why woodpeckers are such successful forest-dwelling birds equipped with drilling, chiseling, and probing abilities unmatched by any other species.