Green woodpecker tongues are so long they wrap around their skulls

When they're not being mounted by renegade weasels, Eurasian green woodpeckers tend to go relatively unnoticed. The birds have an extremely large range, so they're a pretty common sight in the wild. But the same can't be said for their freakishly long tongues.

Image: Emma Shaw

This amazing photograph was shared with us by UK native Emma Shaw, and as you can imagine, it drew its share of scepticism. But let us assure you: the photo is no fake.

The green woodpecker's tongue is quite the marvel – it's so long, in fact, that it has to coil behind the skull, over the eyes and into the right nostril in order to fit inside the bird's head:

(You can also see the internal action in this video, but be warned, it features a dissection and is not for the squeamish.)

Measuring in at ten centimetres (3.9 inches), the woodpecker's tongue accounts for about one third of its body length. For a bit of perspective, if your tongue were that long, it would stretch out at around half a metre (1.5-2 ft).

As is the case with most peculiar body parts in the natural world, there's a resonable explanation here, and it's got to do with food. During the spring and summer months, the green woodpecker's diet consists almost entirely of ants (we've got the poop to prove it).

While a beak is certainly a great tool for rooting around in topsoil, ant nests run deep – and it takes an avian "anteater" to get to them.

The woodpecker's strategy is simple: stick your face into soil or a crumbly fallen log, deploy your sticky mouth appendage, retract and enjoy the tasty spoils.

This same method is used by a motley crew of other species, including echidnas, pangolins (whose tongues are so long they attach to the pelvis!) and other anteaters. It just looks strange on the woodpecker because we're not used to seeing bird tongues (exhibit A: the terror that is the goose tongue).

Interestingly, this isn't the only woodpecker with such a specialised tool, explains the Cornell Lab of Ornithology. Most species have a uniquely shaped tongue that fits their diet and mode of foraging.

"Woodpeckers that excavate deeply into timber, such as the pileated, have shorter tongues with spear-like tips bearing backward-facing barbs," explains Cornell. "Sapsuckers have brush-like tongues that hold the sap of trees by capillary action. Species that feed from crevices and surfaces of trees usually have longer tongues with bristles concentrated at the tip."

In the case of our ground-feeding friend here, the tongue is flattened at the tip, which allows for better contact. Green woodpeckers will also eat seeds, old fruit and other invertebrates, but this dietary shift typically happens during the winter months when their six-legged hors d'oeuvres of choice are difficult to find.

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Top header image: Mark Kilner/Flickr