Archaeologists have discovered numerous ceramic or clay whistles at Aztec sites, dubbed "death whistles" because of their distinctive skull shapes. A new paper published in the journal Communications Psychology examines the acoustical elements of the unique shrieking sounds produced by those whistles, as well as how human listeners are emotionally affected by the sounds. The findings support the hypothesis that such whistles may have been used in Aztec religious rituals, or perhaps as mythological symbols.

Archaeologists unearthed the first Aztec death whistles, also known as ehecachichtlis, in 1999 while excavating the Tlatelolco site in Mexico City. They found the body of a sacrificial victim, a 20-year-old male who had been beheaded, at the base of the main stairway of a temple dedicated to the wind god Ehecatl. The skeleton was clutching two ceramic skull-shaped whistles, one in each hand, along with other artifacts. More skull whistles were subsequently found, and they've found their way into popular culture. For instance, in Ghostbusters: Afterlife (2021), Egon Spengler had such a whistle in his secret laboratory collection.

Scholars have puzzled over the purpose of the skull whistles, although given the dearth of concrete evidence, most suggestions are highly speculative. One hypothesis is that it was used in battle, with hundreds of warriors blowing their whistles simultaneously as a battle cry. Music archaeologist Arnd Adje Both has dismissed that idea, suggesting instead that the whistle's purpose was more likely tied to ceremonial or religious practices, like human sacrifice. Yet another hypothesis proposes that the whistles were intended as symbols of a deity. The skull shape, for instance, might allude to the Aztec god of the underworld, Mictlantecuhtli.