Do woodpeckers’ tongues protect their brains? Here’s what studies show

Could woodpecker skulls hold the secret to mitigating brain damage in humans? Since the 1970s, scientists have asked this question, researching the industrious bird’s skull and brain in a bid to discover how its frequent head banging doesn’t cause irreversible brain damage.

One popular claim (archived) abounded online: that woodpecker tongues wrap around the bird’s skull protecting it from the impact of pecking.

The science website The Brain Maze wrote:

The woodpecker’s tongue is one of nature’s most astonishing adaptations. Far longer than its beak, the tongue extends back into the skull, wrapping around it — sometimes even looping over the top and around the eye socket. This isn’t just to catch insects buried deep within tree bark; it’s also a vital piece of shock-absorbing anatomy.

This claim also circulated online across Instagram (archived), Threads (archived), X (archived), Bluesky (archived) and TikTok (archived).

However, while some birding websites showcase this theory and some scientists have believed it in the past, recent research found that woodpecker tongues have little to do with actually protecting the bird’s brain. Rather, researchers have pecked away at different theories to explain how woodpeckers avoid brain damage, notions that have inspired humans working in fields like crash safety and helmet design.

According to peer-reviewed research published in 2006 (which another peer-reviewed study in 2022 affirmed), woodpeckers avoid damage to their brains while pecking because of the motion itself and the small size and tilted position of their brains — not their long tongues. These factors, in combination with the short duration of individual pecks, allow woodpeckers to withstand much harder hits than those that cause concussions in humans.

Early studies suggest tongue provides some shock absorption

Sir Isaac Newton’s first law of motion dictated that an object in motion stays in motion. Therefore, when woodpeckers slam their heads against a solid object like a tree while pecking, their heads stop moving when they hit the tree, but their brains slam into the inside of their skulls. That impact is called deceleration.

Because of deceleration and Newton’s first law of motion, scientists long assumed that woodpeckers need some sort of built-in protection for their brains. The birds peck at trees to build nests, find food and communicate with each other.

G forces measure acceleration or deceleration, meaning how fast an object speeds up or slows down. One G force is the equivalent of the pull of Earth’s gravity. Humans might experience higher-than-normal G forces in a car crash when the moving car meets a stationary object. Woodpeckers experience G forces when their moving head meets a stationary tree, causing rapid deceleration. And, according to the Field Museum of Natural History, a pecking woodpecker experiences G forces up to 1,400 g. 

It is true that woodpeckers have long tongues that wrap around their skulls. In the past, some researchers assumed this must be how they protect their brains. According to Alex Bond, the principal curator for birds at the Natural History Museum in London, some woodpeckers have tongues up to 10 centimeters long, roughly one-third of their total body length. The birds use their long tongues to search for food deep inside trees.

According to Bond, the tongue of a woodpecker wraps around the hyoid apparatus — a set of bones and muscles that start at the front of the skull by the upper beak — and runs between the woodpecker’s eyes and around the skull before meeting at the base of the lower beak.

Past peer-reviewed research argued that the hyoid apparatus plays a crucial role in protecting the birds’ brains from injury through shock absorption or by creating a safety belt-like sling for the head to slow down the impact of deceleration.

Other peer-reviewed research said special “spongy” bones within the woodpecker’s skull lessen the blowback from powerful pecks.

Meanwhile, researchers in other peer-reviewed studies theorized that woodpecker skulls have evolved to effectively redirect shock waves from pecking, dispersing the impact on the birds’ heads and brains throughout their bodies.

Other research focuses less on the tongue, more on anatomy overall

However, some research dating back to the 1970s questioned whether woodpeckers’ tongues help prevent damage from pecking or whether they needed shock absorption at all.

In 1976, a group of researchers wrote, “It has been suggested that the shock is dampened by the flexible cartilage connecting the base of the beak to the bones of the skull. If this cartilage absorbed much of the impact, however, the beak would not be very effective in boring holes.”

This doubt persisted within the field of woodpecker research for years. Then, in 2022, researchers from the University of Antwerp analyzed high-speed video frame by frame to show that woodpecker skulls actually remain stiff while pecking and the birds seemingly don’t need to cushion their blows. Rather, the 2022 study titled “Woodpeckers minimize cranial absorption of shocks” argued that the birds use their skulls and beaks as “stiff hammers.”

The study’s lead author, Sam van Wassenberg, explained in a video that a regular stiff hammer could make a dent in a tree, but a hammer with built-in shock absorption “is simply a bad hammer.”

The 2022 study confirmed an earlier study in 2006 that found woodpeckers avoid concussions because their heads and brains are much smaller, and differently positioned, than human brains. These factors mean they can withstand larger decelerations without lasting damage.

Professor Lorna Gibson of the Massachusetts Institute of Technology authored the 2006 study. Gibson explained in a series of videos in 2018, “The size matters. The smaller the brain, the larger the deceleration that it can withstand.” Gibson said:

We can say that there’s really three factors that have allowed the woodpeckers to tolerate these high decelerations. One is their small brain size, that was a factor of eight. One is the orientation of the brain, that gave another factor of two. And one is the duration of the impact and that gives a factor of 4. So that altogether there’s a factor of 64. The woodpecker brain should be able to withstand decelerations about 64 times that, that a human brain can tolerate without injury.

Gibson found that woodpeckers can tolerate up to 6,000 Gs of deceleration for pecks lasting between half a millisecond and one millisecond without suffering brain damage. By comparison, according to Gibson, humans suffer brain damage at around 100 Gs of deceleration for three to 15 milliseconds — a lower force but a longer period of time compared to a pecking woodpecker.

In sum …

A myriad of theories has circulated for many years about how woodpeckers protect their brains from injury. However, recent research departed from a long-held assumption that the birds somehow cushion their brains from the impact of pecking. If the birds’ anatomy did somehow cushion their peck, that would only serve to make their pecks less powerful, according to a 2022 study.

The 2022 study backed up Gibson’s 2006 findings and found that a woodpecker’s “cranial skeleton is used as a stiff hammer to enhance pecking performance and not as a shock-absorbing system to protect the brain.” Instead, Gibson pointed to three factors — brain size, orientation of the brain and duration of impact during pecking — that allow woodpeckers to withstand higher impacts than humans without damaging their brains.

As for their tongues — while the hyoid apparatus does wrap around the birds’ skulls, recent research does not support the theory that it functions as a seat belt or cushion to slow down the impact of deceleration.

Sources