The best evidence of prehistoric cannibalism comes from the archaeological record of the American Southwest at sites occupied by the Anasazi people. From the archaeological record, we know that it was practiced for about four centuries, beginning about 900 A.D. It is believed that Southwestern cannibalism originated in Mexico, where the practice was common and dates back to 2,500 years. Cannibalism can be differentiated from all other forms of bone damage and mortuary practices by distinctive features found on human bones that are consistent with marks found on the bones of large and small game animals that were processed for food.
 
 

HUMAN DAMAGE TO BONE

Perimortem modification of animal and human bones at this site includes three primary direct forms- breaking, cutting and burning.

Breaking is commonly caused by impact blows, but can also be done by leveraging, twisting or snapping. Impact breakage is a strong clue that human activity has been involved, especially if the breakage occurs near the midshaft of the bone. (Turner)
 

"Pot Polish"occurs when the inner surface of a cooking vessel creates an abrasive surface that comes in contact with the bone during cooking to produce polish and beveling.
It has long been observed that human bone thought to represent the remains of  cannibalized individuals are remarkably well preserved. One theory is that boiling expels fats from the bone, which retards the process of disintegration.

A common debate is how to distinguish human created cut marks from marks made by other factors such as carnivore and rodent tooth scratches, root etching, abrasion, trampling marks, preparation scratches, and  vascular grooves among others. Use of the scanning electron microscope has greatly aided in the discrimination between human- induced marks and other natural damage.

Burned bone indicates human activity whether the burning was purposeful, such as in cremation or cooking, or haphazard, such as when bones are discarded into a fire pit. When bone is burned, the macroscopic alterations include discoloration (charring and calcining), cracking and exfoliation ( White). This skull shows burning of the back of the head and mandible, but the face and right temporal bone show no burning, possibly because the face and side of the head were driven internally and protected from the fire. (photo: Turner, 1999)
 
 
 

Chopmarks are produced when a stone artifact is used to strike a bone surface with a blow directed roughly perpendicular to the bone surface. Chopmarks are broad and V-shaped in cross section. The humerus below shows cutmarks suitably located for cutting the arm in half at the elbow joint. The midshaft break appears to be post mortem due to its lack of spiraling. ( Turner, 1999)

 
 
 
 
 
 
 

Cutmarks are defined by  multiple slicing marks across the bone produced by a sawing motion of a blade. Stone tool cut marks on bone usually occur near joints such as the mandible, shoulder, elbow, knee, and hip, where dismemberment apparently took place. This femur head has cutmarks encircling the neck where the leg was most likely cut. Similar to cutmarks are scrapemarks, which are produced by drawing a tool across a bone surface, and results in a dense series of usually superficial, parallel striations across a broad area of bone. ( Turner, 1999)

In addition to these telltale signs of human cannibalism, archaeologists found further evidence for cannibalism with the location of the bones found at the site. Many bones that were believed to come from cannibalized individuals were found spread out over the site, indicating that the bones were discarded in different areas after dismemberment.   (White, 1992)

Conjoining is a useful procedure that can tell us information about the sequence of events that took place. In this example, the lower part of the femur has been burned and the upper part has not. This would indicate that the burning took place after the fracture of this bone. (Photo: White, 1992)
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Recently an archaeological team at an Anasazi site recovered ancient human feces, known as copralite, that contained human myoglobin, a protein found only in skeletal and heart muscles. Human consumption did occur, because myoglobin would not be in the feces unless someone had eaten human muscle tissue. Traces of human myoglobin were also detected in a cooking pot found in one of the houses at the site.