Chocolate Chaco

Archaeologist Patricia Crown of the University of New Mexico and collaborator Jeffrey Hurst of the Hershey Center for Health and Nutrition (yes, THAT Hershey) recently published a study in the Proceedings of the National Academy of Sciences where they identified chocolate residue in some ceramic vessels at Pueblo Bonito in New Mexico's Chaco Canyon. Is anyone surprised to find that Native American groups in North America consumed chocolate 1,000 years ago? It's delicious, why wouldn't they have enjoyed this delicious foodstuff as so many others do today?

Archaeologists are VERY excited about this study, and rightfully so -- it's a big deal.  In order to understand why we are so excited, a little background information is required.  When archaeologists talk about Chaco Canyon, they are usually referring to a complex of large stone buildings, pueblos or "great houses", that were constructed in what is now northwestern New Mexico between about AD 1000-1150, although, other groups, including the Navajo, were present in the region at various times.  The largest and one of the longest occupied pueblos in Chaco Canyon is Pueblo Bonito, which includes between 650-800 rooms.  Chaco remains a place of great importance to different modern Native American groups today.

Aerial photograph of Pueblo Bonito

The great houses at Chaco Canyon are unique in the prehistory of the American Southwest, in that the structures were huge and were clustered together in an area that was less than ideal for agriculture.  Archaeologists still hotly debate Chaco, for example some argue that Chaco was occupied by a small number of people for most of the year with other people periodically gathering there for special occasions, and others believe a larger population stayed year-round.  Archaeologists do agree that Chaco was an enormously significant place for the people of the prehistoric southwest, and that Pueblo Bonito was a place of particular importance within the canyon.  Archaeologists also agree that ritual observance was a big part of the Chaco phenomenon, and one indication of this are the larger than expected numbers of imported objects including turquoise and shell jewelry, macaw bones, and unusual ceramic vessels, such as the "cylinder jars" pictured below. 

Example of "Cylinder Jars" from Chaco Canyon*

Less than 200 of these jars have ever been found, and 166 of these jars were found at Pueblo Bonito.  111 jars were found in a single room!

Cache of cylinder jars excavated from Pueblo Bonito

The researchers in this study took some broken pieces of these cylinder jars and some tall-necked pitchers that are sometimes found with them and extracted residues that had been absorbed by the pots.  Chemical tests of the residues revealed the presence of theobromine, a biological marker of cacao (from which chocolate is derived).  Crown and Hurst give four reasons why this discovery is so significant.

First, the chocolate found at Pueblo Bonito was a long way from home.  As seen in this map, the next closest area from which cacao could have been grown is thousands of kilometers from Chaco Canyon.  Someone carried the beans from Mexico or another place in Central America all the way to what is now northern New Mexico.  That there was a special ceramic vessel for consuming chocolate indicates that chocolate was consumed on several occasions, this was not a one-time occurrence.   

Cacao production area relative to Chaco Canyon*

Second, we now know what these unusual vessels were used for.  The Maya and other prehistoric Mesoamerican people consumed chocolate by pouring spiced ground cacao seeds mixed with water from elongated container to container to create a frothy beverage.  We now know that the elongated vessels found at Pueblo Bonito were used for this same purpose.

Third, if Pueblo Bonito was a center of ritual activity during its time, details about a specific ritual performed in that place are extremely interesting.  One of the rituals performed at a center for such activity in the American Southwest has explicit ties to Mesoamerican ritual.  It has long been argued that elite individuals in Chacoan society tied into Mesoamerican ideas.  The presence of the chocolate ritual at Pueblo Bonito supports this connection.

Fourth, that a ritual was performed at Pueblo Bonito fairly exclusively underscores the idea that Pueblo Bonito is at the center of Chaco ritual activity.  That the ritual is explicitly associated with Mesoamerica makes this situation all the more interesting.  

* Figure appeared in the original article by Crown and Hurst in the February 2009 Proceedings of the National Academy of Sciences