The Mystery of the Aztec Death Whistle

As its name suggests, an Aztec death whistle can make a most dreadful sound. But the effect depends on how it's played, explains musicologist and archaeologist Arnd Adje Both of the Free University of Berlin. It’s important to understand how the Aztecs heard them, he explains, roughly 700 years ago.

"I propose a cultural interpretation of these instruments," Both says. "We might have the impression that it's a scream, but it could actually be the impression of the howling wind of the underworld."

Often called "skull whistles," these artifacts have been linked to the Aztec wind god Ehecatl-Quetzalcoatl. Half a dozen of the clay instruments—a few inches long and decorated with terrifying portrayals of grinning skulls—have been discovered at Aztec archaeological sites, first in the late 19th century.

The greatest discovery came in the late 1980s at Tlatelolco, a city near the Aztec capital Tenochtitlán (now central Mexico). Two skulls whistles were found clasped in the hands of a 500-year-old human sacrifice inside a temple dedicated to Ehecatl-Quetzalcoatl.

Through precise x-ray scans, working replicas and ethnological research, Both closely studied the Tlatelolco whistles. Archaeologists don't definitively know how skull whistles were used, but he suggests they had a specific function in Aztec ceremonies relating to death—including human sacrifices. And he emphasizes their purpose can only be interpreted within the context of Aztec religious beliefs.

Aztec death whistles don't represent just any skull, Both says, but a specific one. Distinctive indications of a ceremonial headdress on some examples suggest they represent the skeletal visage of Mictlantecuhtli, the Aztec god of the underworld.

The link between the Tlatelolco whistles and a human sacrifice is also a clue to their purpose, Both says. They could have been used to recreate the sounds of sacred howling winds Aztecs believed separated deeper levels of Mictlan, the underworld realm of Mictlantecuhtli.

Aztec myths convey that these winds grew fiercer as a soul went deeper into Mictlan. Eventually, an "obsidian-bladed" wind stripped the flesh of the newly dead to the bone. When they arrived before Mictlantecuhtli at the lowest level, they too looked like skeletons.

In Aztec belief, the process of death enabled the process of new life, a cycle reflected in the use of skull whistles during important ceremonies, Both explains. He also notes that the human sacrifice took place before a temple dedicated to Ehecatl-Quetzalcoatl, who presided over the divine underworld winds. Ehecatl-Quetzalcoatl and Mictlantecuhtli were often intertwined in myths of creation, death and cosmic renewal.

Looking at the internal structure of the skull whistles, Both describes a tubular stem that is blown into. That stem leads to the top of a globular sound chamber containing an intricate arrangement of three distinct cavities and a final "bell" beneath the face of the skull. When the stem is blown into, the result is an unsettling, oscillating sound combined with a high-pitched tone.

But Both's conclusion about their purpose challenges the work of scientists from the University of Zurich, who proposed in 2024 the whistles were designed to mimic human screams during religious ceremonies.

"The sound itself is really aversive," says neuroscientist Sascha Frühholz, the study's lead author. "You can listen to it, but at some point you just want to say, stop it—I cannot listen to this sound anymore."

"It's a piercing sound," Frühholz adds, "like a human scream." He posits Aztec skull whistles would not have been loud enough to use in warfare, as some have also suggested. Instead, they would have been most effective when used in a closed space, such as for ceremonies—maybe to frighten a sacrificial victim or audience.

An impression of human screams is only created when the skull whistles are blown too heavily, Both counters. He argues they come from a Mesoamerican tradition of creating whistles to reproduce the sounds of nature, such as an animal call—or the sound of wind—and should be blown softly.

In this case, the skull whistles would have recreated the sounds of the underworld’s divine winds: the essential trials that faced an Aztec soul after death.

"You have to know the Aztec culture," Both says. "You have to understand that in order to make a good interpretation."