Like Snow White’s seven dwarfs, shepherds on one of Spain’s Canary Islands whistle while they work and use the sound to communicate over long distances.

No one knows how long the shepherds on the island of La Gomera have used the rare whistled language called the Silbo Gomero, but American and Spanish researchers said on Wednesday that the brain processes it like a spoken language.

“We found that the same areas (of the brain) that are activated for language are also activated for the Silbo,” Manuel Carreiras, of the University of La Laguna on the island of Tenerife, told AMN Health.

He and his colleague David Corina, of the University of Washington in the United States, used functional magnetic resonance imaging to compare how the brain is activated in five Spanish speakers and five shepherds who spoke Spanish and Silbo.

During two tasks, the volunteers listened to sentences in the two languages while the researchers monitored their brain activity.

When the whistlers listened to Silbo sentences, regions in the left side of their brain were activated, including areas linked to language production and comprehension, along with a region in the right hemisphere thought to be associated with linguistic processing.

The brains of the Spanish speakers did not show the same response, which suggests they did not recognize Silbo, according to the scientists, who reported their findings in the journal Nature.

When only Spanish sentences were played, both groups showed the same pattern of bilateral brain activation.

“Our results provide more evidence about the flexibility of human capacity for language in a variety of forms,” Corina said.

“The non-Silbo speakers were not recognizing Silbo as a language. They had nothing to grab on to so multiple areas of their brains were activated. But the Silbadores (whistlers) were analyzing differently, as a language, and engaging those areas associated with language,” he added in a statement.

The Silbo, which is thought to have been brought to the island by Berbers from North Africa, condenses Spanish into two vowels and four consonants.

Whistled languages are also used in Greece, Turkey, China and Mexico, according to Corina.