QuestionPileated woodpecker
How Long Is a Woodpecker's Tongue? Wrapped Around the Skull
A woodpecker’s tongue can reach several centimeters beyond the tip of its bill, in some species farther than the bill itself is long. The northern flicker, an ant-eating woodpecker of North America, can stick its tongue out about 5 cm (2 in) past its bill. This is possible because the bones supporting the tongue loop around the back and top of the skull.
Contents
How long are woodpecker tongues?
The exact length varies with the species and its diet. Woodpeckers that dig ants and larvae out of deep tunnels have the longest tongues, while sapsuckers, which lick sap from shallow wells, have relatively short ones.
| Woodpecker | Tongue | Main food |
|---|---|---|
| Northern flicker | Extends about 5 cm (2 in) past the bill; sticky | Ants, often dug from the ground |
| Pileated woodpecker | Long, barbed and sticky | Carpenter ants and beetle larvae in wood |
| Green woodpecker (Europe) | Very long and sticky | Ants dug from lawns and meadows |
| Sapsuckers | Short, with a brush-like tip | Tree sap and insects caught in it |
Precise measurements of the whole tongue are rarely given in field guides, because most of it is hidden inside the head when the bird is at rest. What is clear is that in long-tongued species, the tongue apparatus is far longer than the bill.
How does the tongue wrap around the skull?
The secret is the hyoid apparatus, the set of slender bones and cartilage that supports the tongue in all birds. In most birds these bones are short and sit in the throat. In woodpeckers, the paired rear branches, called horns, are enormously long.
From the base of the tongue, the two horns run back under the jaw, curve around the back of the skull, pass over the top of the head under the skin, and end near the forehead. In some species they reach the base of the bill or even run into a nostril. Each horn is wrapped in muscle.
When those muscles contract, they push the hyoid forward around the skull, and the tongue shoots out of the bill. When other muscles pull it back, the tongue slides in again and the horns return to their curve around the head. The system works rather like a tape measure or a sliding sheath.
Barbs, glue and brushes: tongue tips
The tip of a woodpecker’s tongue is a precision tool matched to the bird’s food.
- Barbed tips: Wood-boring specialists have a hard, pointed tip covered with tiny backward-facing barbs that catch on the soft bodies of beetle larvae.
- Sticky tongues: Large salivary glands coat the tongue with sticky saliva, which is especially important for ant-eaters like flickers, green woodpeckers and pileated woodpeckers.
- Brush tips: Sapsuckers have a shorter tongue fringed with fine, hair-like projections that soak up sap by capillary action, a bit like a paintbrush.
For many years, people believed woodpeckers speared grubs on their tongues. Detailed studies published in 2004 showed that the barbed tip more often hooks and wraps around the prey, which is then pulled out of its tunnel. The tongue can also bend and probe around corners in winding galleries.
How woodpeckers use their tongues to feed
Feeding usually starts with the bill. A woodpecker taps, listens and chips away wood until it opens a tunnel, as explained in why do woodpeckers peck wood? Then the tongue takes over, reaching deep into the gallery to find and extract the prey without the bird having to dig out the whole tunnel.
Ant-eating woodpeckers use their sticky tongues differently. A flicker or green woodpecker pokes its bill into an ant nest in the soil and flicks its tongue in and out, collecting ants and their larvae by the hundreds. Pileated woodpeckers do the same inside the galleries of carpenter ant colonies in dead wood.
Does the tongue protect the brain?
Because the hyoid wraps around the skull, it is often described as a “safety belt” that cushions the brain during pecking. This idea is widely repeated, but it has little direct evidence behind it. High-speed studies of pecking woodpeckers suggest the head does not absorb much shock at all, and that the birds avoid injury mainly because their brains are small. The full story is in why don’t woodpeckers get headaches?
The hyoid’s main job, as far as scientists can tell, is simply to make an extremely long, mobile tongue fit inside a small head.
Other animals with remarkable tongues
Woodpeckers are not the only animals that store a long tongue in a clever way.
- Hummingbirds have forked tongues whose supporting bones also curve around the back of the skull, letting them lap nectar from deep flowers.
- Chameleons fire a tongue that can be longer than their body at extraordinary speed; see how fast is a chameleon’s tongue?
- Anteaters and pangolins have very long, sticky tongues anchored deep in the body, a solution to the same problem of eating ants and termites.
That several unrelated animals evolved long, sticky or brush-tipped tongues for similar foods is a classic example of convergent evolution.
Frequently asked questions
Does a woodpecker's tongue wrap around its brain?
Not around the brain itself. The bones that support the tongue, called the hyoid apparatus, run from the throat around the back and over the top of the skull, outside the braincase, and in many species end near the forehead or in a nostril.
Where does a woodpecker keep its tongue?
When the tongue is pulled in, most of its length lies inside the bill and throat, while its long supporting bones and muscles curve around the outside of the skull under the skin. The arrangement works like a sheath that lets the tongue slide far out and back again.
Is a woodpecker's tongue sticky?
Many woodpeckers have sticky saliva that coats the tongue, especially ant-eating species such as flickers. Wood-boring species also have backward-pointing barbs on the hard tongue tip.
Do woodpeckers spear insects with their tongues?
This was long believed, but more detailed studies have shown that the barbed tip usually hooks and wraps around a larva or ant rather than impaling it, before the bird pulls it out of the tunnel.
Which bird has the longest tongue compared to its size?
Woodpeckers and hummingbirds both have exceptionally long tongues for their size. Among animals in general, chameleons are famous for tongues that can be longer than their own bodies.
Sources and further reading
- Cornell Lab of Ornithology, All About Birds, "Northern Flicker"
- Animal Diversity Web (University of Michigan), "Picidae"
- Winkler, H., Christie, D. A. and Nurney, D., Woodpeckers: A Guide to the Woodpeckers, Piculets and Wrynecks of the World (1995)
Cite this page
“How Long Is a Woodpecker's Tongue? Wrapped Around the Skull.” Animal Atlas, https://animals.bigworldlist.com/questions/how-long-is-a-woodpecker-tongue/.
