It’s a simple object about the size of a modern pen: two parallel cactus spines, stained black at the tips and lashed with split yucca leaves to an 89mm (3.5-inch) handle of skunkbrush sumac. But its simplicity hides its significance. Sometime around the start of the Common Era, an Ancestral Pueblo person living in what is now southeastern Utah got a tattoo in black ink. 2,000 years later, archaeologists unearthed the needle, and about 40 years after that, Andrew Gillreath-Brown found it in a box in museum storage, with the ink still staining the tips of the cactus-spine needles.

Gillreath-Brown studied the black pigment under a scanning electron microscope to get a better look at its crystalline structure, and he analyzed its chemical composition with x-ray fluorescence. It turned out to be high in carbon, which is still true of many body paints and tattoo inks in use today. At 2,000 years old, the tool is the oldest tattooing implement ever discovered in western North America, and it’s a clue to a part of prehistoric North American culture that archaeologists still know very little about.

Tattoos have played an important role in many cultures around the world, but anthropologists don’t understand as much as they'd like about the origins of the art form. That's in part because so little evidence remains, and what little we can see is sometimes just as enigmatic as a stranger’s tattoos can be today.

Otzi, a man who died about 5,000 years ago and ended up mummified in an Alpine glacier, had a remarkably well-preserved set of tattoos that, based on their location, may have been a product of a Western version of acupuncture. But we can’t be sure, because neither Otzi nor his tattoo artist left us a note about their meaning. In the southwestern US, where archaeologists have never found any ancient people’s remains with tattoos preserved, we know even less about what prehistoric body art looked like, how it was made, and what it meant to its bearers.

It seems that people in the Southwest did practice tattooing, though, because artwork on ceramics and rock walls sometimes depicts human figures with tattoo-like markings. Archaeologists have found a few tattooing tools at sites in New Mexico and Arizona, with the oldest ones dating back around 920 to 740 years. Now we know they look pretty similar to the much older needle Gillreath-Brown unearthed in the museum collection, cactus spine tips and all.

“Tattooing by prehistoric people in the Southwest is not talked about much because there has not ever been any direct evidence to substantiate it,” said Gillreath-Brown in a statement to the press. “This tattoo tool provides us information about past Southwestern culture we did not know before.”

That’s a significant step forward, since so much detail about the life and culture of Ancestral Pueblo people, and those of other southwestern US cultures from the same time period, have been lost over the intervening centuries. We know that they were hunter-gatherers until sometime shortly before 500 BCE, when they began cultivating maize and settling into a more sedentary lifestyle in pit houses. We know they made baskets and painted distinctive figures and symbols on rock outcrops around the American southwest. But a few drops of ink on the end of a needle offer a much more personal connection with these ancient people.

Journal of Archaeological Science: Reports, 2019. DOI: 10.1016/j.jasrep.2019.02.015;(About DOIs).