When it comes to the "flexible tongue" skill, certain tongue length and muscle tone are a must. In addition to genetics, the environment can also be a factor in this trait’s formation. For example, Indians are particularly likely to have flexible tongues. Scientists believe that this has to do with the peculiarities of their language.
The extent of tongue flexibility may vary. Researchers even went as far as to conduct a special study on the subject. 63% of the test participants managed to fold their tongue into a roll, 14% managed to bend it in half, and less than 1% were able to shape their tongue into a triple pipe.