Frog Tongue: Everything There is to Know

Frogs have several characteristics that make them unique creatures, but their most distinctive feature by far is their tongue. These incredible muscular organs are essential to a frog’s survival, especially to catch prey. However, most people know very little about frog tongues apart from the fact that they’re long and can snatch flies out of thin air.

Frog tongues are muscle tissue used primarily for hunting prey. This extremely soft appendage is 10x softer than a human tongue, typically 1/3 the length of a frog’s body, and is coated in unique reversible saliva that can both liquefy and solidify in order to capture and maintain its grip.

Even more remarkable is the speed at which frogs can launch their tongue out of their mouth. If you’re a frog enthusiast or simply curious about the tongue-related abilities of these fascinating amphibians, we urge you to read on. In this article, we’ll answer some of the most commonly asked questions about frog tongues regarding their length, stickiness, speed, and more.

How Do Frogs Catch Prey With Their Tongue?

Frog tongues are made of muscle tissue composed of cells that have the special ability to shorten or contract in order to produce movement. This extremely soft appendage is coated in unique reversible saliva that can both liquefy and solidify in order to capture and maintain its grip.

Considering a frog’s tongue moves far faster than any human eye can perceive, it can be difficult to discern how they can catch prey effectively. Do their tongues wrap around the insects and pull them in, or do they stick to the prey like a high-quality adhesive?

Frogs capture their prey by covering them in some of the stickiest saliva known to science made from a non-Newtonian fluid. This saliva is secreted from thousands of mucus glands and transforms from a liquid to a solid and back, making it easy to catch and grip insects.

The method frogs use to capture their prey is incredible, thanks to this unique, reversible saliva. As opposed to humans that have salivary glands in their mouth to produce spit, frog’s tongues themselves can generate saliva even when it is no longer attached to the frog (Alexis, 2017).

When in the frog’s mouth, the saliva takes a more solid form that is 5x thicker than honey so that the tongue does not stick to the inside of the frog’s mouth and causes eating or respiratory issues. However, when the frog is hunting, it will shoot and envelope its tongue around the targeted insect. 

Once the tongue has wrapped around its prey, the once thick saliva liquefies and coats the insect before it quickly switches back to its sticky form so as not to lose its grip. With the insect firmly stuck to the frog’s tongue, it can now retract it into its mouth.

However, because a frog’s saliva is usually thick when not enveloping prey, it can be difficult to swallow, particularly when an insect is also in its mouth. To solve this issue, the frog will swallow by closing its eyes to push its eyeballs down into its head because the force of this action re-liquifies its saliva and makes swallowing easier.

How Long is a Frog’s Tongue?

When you see a frog’s tongue launch from the depths of their mouths, most people are astounded by its length, as it seems to go on endlessly until it collides with its intended target. 

As a general rule, a frog’s tongue is roughly 1/3 the length of the frog’s entire body. Therefore, an African Bullfrog that is 9 inches long would typically have a 3-inch long tongue.

Here are some examples of frog tongue length based on some frog species and their average sizes:

Frog SpeciesAverage Frog Size (Inches)Tongue Length (Inches)
Beelzebufo (Extinct)16.7 in5.56 in
Goliath Frog11.2 in3.7 in
African Bullfrog9.0 in3 in
American Bullfrog6.5 in2.16 in
Poison Dart Frog1.47 in.49 in
Wood Frog2 in.66 in
Gray Treefrog1.75 in.58 in
Spring Peeper1.24 in.41 in
Paedophryne Amauensis.3 in.1 in

Therefore, smaller frogs, such as tree frogs or Spring Peeper, have tongues that are typically less than an inch long, while larger species, such as the Goliath Frog, may have a tongue measuring up to three to four inches in length, considering their overall average size is around 11.2 inches long. 

Still, the average human tongue length is about 3 inches, which means some of the largest frog species have tongues that are relatively the same length as ours despite being a tiny fraction of our size. 

Average Speed & Force Behind a Frog’s Tongue

Even more astonishing than the length of a frog’s tongue in proportion to their overall body length is the speed and force with which they can essentially rocket this appendage out of their mouths. 

Because frogs use their tongues for hunting, they have to catch prey with significant speed if the animal has any hope of eating that day and ultimately surviving. Luckily, frog tongues have evolved to be launched at speeds the human eye can barely perceive.

The average frog’s tongue can be released from its mouth, grab prey, and return in a mere .07 seconds and pull items that weigh up to 1.4 times the frog’s body weight. Additionally, insects captured by the frog’s tongue can experience 12 times the acceleration of gravity (or 12 Gs of force). 

For a point of comparison, astronauts will experience about 3 Gs of force during a rocket launch. So, the sheer force these insects feel is certainly enough to leave them stunned if they even had the time to register the impact.

The speed that a frog’s tongue moves is 5 x faster than a human can blink, which spells a quick death for anything unfortunate enough to be stuck to a frog’s impressive tongue. 

How Does a Frog’s Tongue Handle That Much Force?

Considering the unearthly amount of force behind a frog’s tongue, one might wonder how such a small and squishy muscle doesn’t just rip out of a frog’s tongue whenever it attempts to hunt for prey. You might assume its tongue must be incredibly strong, but on the contrary, it is its softness that makes this possible (CTNF).

Research has discovered that the biological material that makes up a frog’s tongue is one of the softest in existence (Alexis, 2017). Comparatively, it is ten times softer than a human’s tongue and relatively equivalent to human brain tissue. 

It is this material that allows a frog to safely shoot its tongue at targets with such speed and not risk the integrity of this muscle. The soft, stretchy material functions as a sort of spring or bungee cord that absorbs and stores the force the tongue experiences upon impact and allows the tongue to maintain its grip on its prisoner and safely return to the frog’s mouth. 

More About Frog Tongues

As far as predators are concerned, the frog might not seem like much of an adversary, but knowing the power, speed, and sheer stickiness behind their weapon of choice renders them a formidable foe. 

We, humans, are lucky these amphibians are far too small to be targeting us any time soon. Sadly, once a frog has its next meal in sight, most insects and even small birds and mice don’t stand a chance as its once-thriving life is snuffed out in mere fractions of a second. 

Learn even more about frogs and how they use their tongues in the guides on our blog:

Common Questions About Frog Tongues

What is a frog’s tongue called? A frog’s tongue does not have any particular appellation although the scientific name for the tongue is lingua. Biologists may therefore refer to a frog’s tongue as its “lingua.”

How sticky is a frog’s tongue? The average frog’s tongue can be released from its mouth, grab prey, and return in a mere .07 seconds and pull items that weigh up to 1.4x the frog’s body weight. Additionally, insects captured by the frog’s tongue can experience 12x the acceleration of gravity (or 12 Gs of force).

What’s different about a frog tongue?  Frogs tongues are about ⅓ their body length, 10x softer than a human tongue, and can travel at speeds 5x faster than a human can blink. Additionally, insects captured by the frog’s tongue can experience 12x the acceleration of gravity (or 12 Gs of force).

Do Frogs have split tongues? Generally, frogs do not have forked tongues but they may have a slight spit at the tip of their tongues or a larger tongue tip to better wrap around and grip their prey.

How strong is a frog’s tongue? Frog’s tongues are very strong with the ability to release, grab prey, and return in a mere .07 seconds and grab items that weigh up to 1.4x the frog’s body weight. Additionally, insects captured by the frog’s tongue can experience 12x the acceleration of gravity (or 12 Gs of force).

How long are frog’s tongues? As a general rule, a frog’s tongue is roughly 1/3 the length of the frog’s entire body. Therefore, an African Bullfrog that is 9 inches long would typically have a 3-inch long tongue, and a Spring Peeper that is 1.24 in would have a .41 in tongue length.

Sources

Most of the content of this article was based on the following study by Alexis C. Nobel et al.:

Alexis C. Noel, Hao-Yuan Guo, Mark Mandica, David L. Hu. Frogs use a viscoelastic tongue and non-Newtonian saliva to catch prey. Journal of The Royal Society Interface, 2017; 14 (127): 20160764 DOI: 10.1098/rsif.2016.0764

Physics.gatech.edu, Frog Tongue High Speed Adhesive

Healthline, How Long is the Average Human Tongue?