Samuel Belknap III, a University of Maine graduate student doing research for his thesis on ancient diets in southwest Texas, has found bone fragments of the oldest known domesticated dog in the Americas. The fragments were in an intact ancient human stool sample, indicating that 9,400 years ago people were using dogs not just as companions, workers and guardians, but also as food.

The paleofecal sample was discovered in the 1970s in Hinds Cave, an archeological motherlode in a small canyon of the lower Pecos River, near the Mexican border. Hunter-gatherers lived in the area for 9,000 years, starting before 8,000 B.C. and persisting until as recently as a thousand years ago.

Belknap and fellow UMaine graduate student Robert Ingraham first visually identified the bone as a fragment of the right occipital condyle, the place where the skull articulates with the atlas vertebra of the spine. Ingraham also visually identified the bone at Harvard University’s Museum of Comparative Zoology, which indicated that the fragment closely matched that of a short-nosed Indian Dog from New Mexico.

The bone was then sent to University of Oklahoma researcher Cecil Lewis, who runs the Molecular Anthropology Ancient DNA Laboratory, for DNA analysis. The DNA analysis from the lab, along with a 2002 genetic study of archaeological dog specimens, supported the conclusion that BE-20 is from a domestic dog rather than a wolf, coyote or fox, and is closely related to a species of Peruvian dog.

The age of the bone and the paleofecal material were both radiocarbon dated, confirming that they were contemporaneous and really, really old. This is an important element because previously researchers thought they had found bones of even older dogs (about 11,000 years old) in the Jaguar Cave in Idaho, but that date was based on the archaeological context. When the bones were carbon dated, they turned out to be far more recent, just 1,000 to 3,000 years old.

Judging from the size of the bone (just 1.5 centimeters or a half inch long), Belknap thinks the dog was fairly small, about 25-30 pounds. He’s thinking it might have been chopped up into a stew, which would also explain the second bone he found that is too small to analyze but may be from the dog’s foot.

According to ethnographic studies, dogs were consumed either in times of desperation or times of celebration. Dogs were butchered in a specific way and may have been cooked in a stew, which could explain how bones from a skull and wrist or ankle ended up in the same paleofecal sample.

“It could be that the smaller bones broke off in the butchering process and found their way into a stew or soup,” Belknap said.