Open your mouth and stick out your tongue. (It's OK, no one's looking.) Now, try and make it into a funny shape. Can you roll your tongue, lifting the two sides up to form a "U"? Or, can you twist your tongue into the bumpy shape known as a cloverleaf tongue or a trefoil tongue?
If so, you've got a talent that many people don't have. But why are some people able to twist their tongues into unusual shapes and others aren't? It might turn out that what you thought you knew about tongue rolling is all wrong.
Tongue Rolling and Your Genes
If you took biology in high school or middle school, your class most likely included a unit on genetics and Gregor Mendel, the "father of modern genetics." Using pea plants, Mendel found that inherited genes play a role in determining the traits living things develop. If you are color blind, for example, it's because you inherited the gene for color blindness from at least one of your parents.
In an attempt to spice things up, teachers often use unusual traits as a way to demonstrate how genes work. One of those traits is whether a person can roll their tongue or not. But here's where things get tricky. Your genes might not actually have much to do with whether or not you can roll your tongue, PBS NewsHour points out. The belief that the ability to roll the tongue comes from a gene dates back to 1940 and research conducted by a scientist named Alfred Sturtevant.
It would be putting it mildly to say that Sturtevant's research was flawed. BBC notes a few of the kids in his study refused to open their mouths. Instead of not including them in the study, he put those kids in the "not able to roll their tongues" category. Additionally, Sturtevant found that some of the kids in the study could roll their tongues, even though their parents couldn't, a fact that pretty much instantly disproves his dominant gene hypothesis.
Eventually, Sturtevant reversed course and realized that his hypothesis that tongue rolling is caused by a dominant gene wasn't quite right. He even later apologized for the mistake. But he might have been a bit too late, as decades later, students across the U.S. are still being taught that tongue rolling is a genetic trait.
What About the Cloverleaf Tongue?
In terms of fun shapes you can make with your tongue, the cloverleaf or trefoil tongue is one of the rarest options. The shape has been puzzling scientists for a few decades. A note published in a very old (1949) issue of the Journal of Heredity states that "at least four people in the United States" can shape their tongue into a cloverleaf pattern. For what it's worth, the four people weren't related to each other.
The 1949 note sparked a discussion about tongue shapes, with a scientist reporting in a 1951 edition of the Journal of Heredity that 11 out of 163 women at a college in Virginia were able to make the cloverleaf shape with their tongues. Out of that group of 11, just five had family members who could also make the shape.
A study published in Issues in Anatomy, Physiology, Metabolism, Morphology, and Human Biology in 2013 looked at the types of tongue movements that 429 students in Shaanxi, China could make. While nearly 64 percent of the students could roll their tongues and 14 percent could twist the tongue, none could form their tongues into a cloverleaf shape.
Can You Teach Yourself to Roll Your Tongue?
Interestingly enough, one of the factors that might affect the movements you are able to make with your tongue is the language you speak. A study published in the Journal of Clinical & Diagnostic Research examined the tongue movement abilities of 450 medical students in Malaysia. The students came from three ethnic groups (Malay, Malaysian Chinese and Malaysian Indian) and spoken several different languages.
The languages spoken by the Malaysian Indian students were ones that typically require a fair amount of tongue movements, according to the study, and the researchers found that the Malaysian Indian students were also more likely to be able make the greatest number of different tongue movements. The findings led the researchers to conclude that the lingual demands of a person's language can have some effect on their ability to make certain tongue shapes and movements.
What does that mean for you? If you'd like to roll your tongue or shape it into a cloverleaf, it might be that practice can make perfect. As PBS Newshour notes, out of a group of 10 students, one person was able to learn to roll their tongue after a week of practicing. Maybe it's time to go make some faces at the mirror.