Guila Naquitz (Mexico) - Key Evidence of Maize Domestication History

Understanding American Plant Domestication

Teosinte at the Ethnobotanical Gardens in Oaxaca City
Teosinte at the Ethnobotanical Gardens in Oaxaca City. Bernardo Bolaños

Guilá Naquitz is one of the most important archaeological sites in the Americas, recognized for its breakthrough discoveries in understanding plant domestication. The site was excavated in the 1970s by U.S. archaeologist Kent V. Flannery, using pioneering methods of environmental and ecological sampling. The results of those sampling techniques at Guila Naquitz and other excavations that followed rewrote what archaeologists had previously understood of the timing of plant domestication.

Key Takeaways: Guilá Naquitz

  • Guilá Naquitz is an archaeological site in a small cave in the Mexican state of Oaxaca. 
  • The site was occupied by hunter-gatherers between 8000–6500 BCE. 
  • It is notable for the evidence of teosinte, the progenitor plant of domesticated maize, as well as the domestic plant itself. 
  • Guilá Naquitz was also the first site excavating techniques of environmental and ecological sampling. 

Site Description

Guilá Naquitz is a small cave occupied by local hunter-gatherers at least six times between 8000 and 6500 BCE, by hunters and gatherers, probably during the fall (October to December) of the year. The cave is in the Tehuacán valley of the state of Oaxaca, Mexico, about 3 miles (5 kilometers) northwest of the town of Mitla. The mouth of the cave opens near the base of a large ignimbrite cliff rising ~1000 feet (300 meters) above the valley floor.

The earliest information on the domestication of many of the American domesticated crops—maize, bottle gourd, squash, and beans—was found in the 1950s and 1960s within deposits explored in five caves in Mexico. Those were Guilá Naquitz; Romero’s and Valenzuela’s caves near Ocampo, Tamaulipas; and Coxcatlán and San Marcos caves in Tehuacán, Puebla.

Chronology and Stratigraphy

Five natural strata (A-E) were identified in the cave deposits, which extended to a maximum depth of 55 inches (140 centimeters). Unfortunately, only the top strata (A) can be conclusively dated, based on radiocarbon dates from its living floors and pottery which matches Monte Alban IIIB-IV, ca. 700 CE. The dates of the other strata within the cave are to an extent contradictory: but AMS radiocarbon dates on the plant parts which were discovered within layers B, C, and D have returned dates to nearly 10,000 years ago, well within the Archaic period and, for the time it was discovered, that was a mind-blowingly early date.

A considerable and heated debate occurred in the 1970s, particularly about the radiocarbon dates from Guila Naquitz's teosinte (the genetic precursor to maize) cob fragments, concerns which largely dissipated after similarly old dates for maize were recovered from the San Marcos and Coxcatlan caves in Oaxaca and Puebla, and the Xihuatoxtla site in Guerrero.

Macro and Micro Plant Evidence

A wide range of plant food was recovered within the cave deposits of Guilá Naquitz, including acorns, pinyon, cactus fruits, hackberries, mesquite pods, and most importantly, the wild forms of bottle gourd, squash, and beans. All of those plants would be domesticated within a few generations. Other plants attested at Guila Naquitz are chili peppers, amaranth, chenopodium, and agave. The evidence from the cave deposits includes plant parts—peduncles, seeds, fruits, and rind fragments, but also pollen and phytoliths.

Three cobs with plant elements of both teosinte (the wild progenitor of maize) and maize, were found within the deposits and direct-dated by AMS radiocarbon dating to about 5,400 years old; they have been interpreted as showing signs of incipient domestication. Squash rinds were also radiocarbon dated, returning dates of approximately 10,000 years ago.

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