A publication of the Archaeological Institute of America
Mexico's Butterfly Warriors
The annual monarch migration may have been a sacred event for the people of Mesoamerica
Overnight temperatures in the fir forests of central Mexico hover just above freezing in January. It’s the ideal temperature for the enormous colonies of monarch butterflies that, in late August, begin their 3,000-mile migration south to this small mountainous region. They overwinter until March, when they begin the journey back to the north. This sliver of fir forest, first discovered by biologists in 1975, has a microclimate that draws the monarchs that spend their summer months in the vast swath of Canada and the United States east of the Rocky Mountains. Scientists estimate that by October, when all the butterflies have arrived, each acre occupied by a colony can hold up to 25 million monarchs. It’s thought that, even though monarch butterfly populations have dropped 84 percent in just the last two decades, more than a billion of the colorful insects still find their way home to a protected reserve in the mountains of Michoacan State and Mexico State every year.
For nearly two millennia, butterflies have been vital to the belief systems of the Indigenous people of central Mexico. The Aztecs, also called the Mexica, viewed butterflies as the embodiment of the souls of warriors slain in battle. Archaeologists have discovered evidence of the widespread prevalence of butterfly symbols at such cities as Teotihuacan, which flourished from 100 B.C. to A.D. 650, and Tula, the capital of the Toltec people from about A.D. 850 to 1150. University of Copenhagen Mesoamericanist Jesper Nielsen is exploring the possibility that the tradition of depicting butterflies that began at Teotihuacan is linked to the symbolic significance ancient people may have attached to the annual monarch migration.
In pre-Columbian times, this migration involved even more butterflies than the mind-boggling one billion that fly to central Mexico today, and the insects may have once overwintered much closer to cities such as Teotihuacan and the Mexica capital of Tenochtitlan in forests that no longer exist. “Observing so many monarch butterflies every year at the same time may have been the basis for the idea of the return of dead warriors to the world of the living,” says Nielsen. “The monarchs arrive from the north, and in many traditions in central Mexico, that cardinal direction is associated with death.” It’s possible that the ritual commemorations of the dead that the Mexica held in the fall, and that endure in the form of Mexico’s Day of the Dead holiday, can be traced to the monarch butterflies’ yearly journey.
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