The Woodpecker Tongue: A Barbed and Sticky Probe

The woodpecker’s tongue is a marvel of natural engineering. It  combines exceptional length, sticky surface, and barbs to extract insects from deep within trees. This remarkable organ, controlled by a unique hyoid apparatus, can extend up to 5 inches beyond the bill in some species. Its structure and function vary among woodpecker species, reflecting their diverse foraging strategies.

The Hyoid apparatus is a complex structure of bones, muscle and cartilage that supports the tongue and allows it to extend and contract. It also acts as an elastic layer; a solid, springy and bony support for the tongue.

Woodpecker Tongue: Parts and Structure

The Hyoid Apparatus: The Engine of Extension

The incredible extension of the woodpecker’s tongue is made possible by a unique anatomical structure called the hyoid apparatus. This complex system of bones and muscles controls tongue movement.

Elongated Hyoid Horns: The hyoid apparatus features exceptionally long, flexible “horns” that wrap around the skull. These horns slide forward in their sheaths, pushing the tongue outward.

Anchoring for Maximum Extension: The hyoid horns are anchored near the nostril or around the eye, depending on the species. This anchoring provides a firm base for the extension and retraction of the tongue.

Sticky and Barbed: The tongue’s surface is sticky, coated with a specialized saliva, and often equipped with barbs. These features help secure insect prey and draw them out of their hiding places.

Exceptional Length: Woodpecker tongues are incredibly long relative to their head size, allowing them to probe deep into wood without extensive excavation. Some species can extend their tongues up to 5 inches (13 cm) beyond their bills.

As reference, the table below lists the largest, the smallest and a medium sized woodpeckers:

Woodpecker SpeciesAverage Tongue Length
Downy Woodpecker (smallest)2.5 inches
Pileated Woodpecker (Largest)4 inches
Northern Flicker (medium size)3.5 inches

Tongue Length Correlates with Foraging Style: The length of the tongue varies among species, reflecting their foraging strategies:

  • Shorter Tongues for Excavators: Species like the Downy Woodpecker, which primarily excavate for food, have relatively shorter tongues.
  • Longer Tongues for Probers: Species like the Northern Flicker, which rely more on probing crevices and surface feeding, have relatively longer tongues.

Uses of the tongue by woodpeckers

The woodpecker’s tongue is a remarkable tool that plays a crucial role in their feeding habits. It’s primarily used for finding food, especially insects that burrow deep within trees. The tongue’s incredible length allows woodpeckers to access these hidden insects, pulling them out from crevices and holes.

Here’s how they use their tongues to secure a meal:

  • Extracting insects: The tongue’s extended reach helps in pulling insects out from deep within the tree bark.
  • Lapping up sap: Some woodpeckers (sapsuckers) have a brush-like tip on their tongue, perfect for lapping up tree sap.
  • Grabbing grubs: The tongue’s sticky saliva and tiny barbs on the tip help catch and hold onto slippery insects, preventing them from escaping.

What happens to the tongue of a woodpecker when it is not in use?

Unlike a human tongue, a woodpecker’s tongue doesn’t just sit in its mouth. It’s rooted inside the bird’s skull. When the woodpecker isn’t using its tongue, it curls up behind the back of the head. In some species, the tongue even wraps around the eye sockets.

What makes a woodpecker tongue different from the tongue of other birds?

Red-bellied Woodpecker

The woodpecker tongue stands out in the avian world for its unique combination of length, mobility, and structure. While most birds have short, flat tongues primarily used for swallowing, the woodpecker’s tongue is a highly specialized tool adapted for extracting insects from deep within trees.

Here’s a closer look at how the woodpecker tongue differs from those of other birds:

Length: The woodpecker’s tongue can be incredibly long, sometimes even twice the length of its beak, allowing it to reach deep into tree bark crevices. In contrast, most birds have relatively short tongues that are not designed for probing or extracting food.

Structure and Function: The tip of the woodpecker’s tongue is covered in tiny barbs and coated with sticky saliva, which helps it snag and hold onto insects. This is a stark contrast to the tongues of birds like owls, which are designed to swallow prey whole.

Storage: When not in use, the woodpecker’s tongue retracts and coils around the back of the skull, sometimes even encircling the eye sockets. This unique storage mechanism not only protects the brain during pecking but also highlights the exceptional length of the tongue. Most birds don’t have this elaborate tongue storage system.

Debunking the Spearing Myth: A common misconception about woodpecker tongues is that it was once thought that woodpeckers used their tongues to spear grubs. More detailed studies have revealed that the tongue actually wraps around the prey before being pulled out.

In conclusion, the woodpecker’s tongue exemplifies evolutionary adaptation, enabling these birds to thrive in their ecological niche. Its remarkable length, specialized structure, and unique storage mechanism allow woodpeckers to efficiently extract hidden insects and sap. This fascinating adaptation highlights the intricate relationship between anatomy and behavior in the natural world, showcasing the ingenuity of evolution in shaping survival strategies.

See also: Regional Guides to the Woodpeckers of North America

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References and Sources:

  • Allaboutbirds.org)
  • Gill, Frank B., 1994. Ornithology – 2nd Edition, W. H. Freeman and Company.
  • The Sibley Guide to Bird Life and Behavior, 2001. Chris Elphick, John Dunning, and David Sibley (eds). Alfred A. Knopf, New York.

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