How did the ancient Pueblos come to have cacao beans in the desert, more than 1,200 miles from the nearest cacao trees? Ms. Crown, a University of New Mexico anthropologist, noted that maize, beans and corn spread to the Southwest after being domesticated in southern Mexico. Earlier excavations at Pueblo Bonito, the largest structure in the Chaco complex, had found scarlet macaws and other imported items.

Image Researchers believe ancient Pueblos used the jars to drink chocolate. Credit... Marianne Tyndall

Dorie Reents-Budet, a curator at the Museum of Fine Arts in Boston and a Smithsonian Institution research associate specializing in Mayan cylinder vases, said that a sophisticated Mesoamerican trade network extended to Chaco in the north and as far south as Ecuador and Colombia.

The Mayan vessels, decorated with court scenes and hieroglyphics, were used to ceremonially consume chocolate at sumptuous feasts, Ms. Reents-Budet said. An expensive luxury, the cacao beans were fermented, roasted and ground up, then mixed with water and flavorings before being whipped into froth. It made sense to present the beverage in a special vessel, she said.

“It’s as if you were having a dinner party and serving Champagne,” said Ms. Reents-Budet. “You serve Champagne in really nice glasses.”

After an exchange with Ms. Reents-Budet in October 2007 about the resemblances between the Chacoan and Mayan earthenware, Ms. Crown said she thought about having the Chacoan cylinders checked for cacao residue.