A culture flourished along the central Peruvian coast from about A.D. 900 to 1500. Called the Chancay, they left behind a wealth of cultural remains, including intricate tattoos that are preserved to this day on the skin of mummified individuals.
New details of these tattoos that were previously hidden to the naked eye, including finely traced lines, were described in a study published on Monday. After illuminating the mummies with laser-stimulated fluorescence, or L.S.F., an imaging tool that until now had never been applied to tattoos, scientists discovered lines 0.1 to 0.2 millimeters wide, narrower than work produced by most modern tattoo needles.
“We were shocked by just how fine the tattoo lines were in our L.S.F. images,” said Michael Pittman, an assistant professor at the Chinese University of Hong Kong and an author of the new study in Proceedings of the National Academy of Sciences, in an email. “We immediately knew that what we were seeing was special.”
The mummies featured in the new study had been buried at the Cerro Colorado cemetery, and were rediscovered in 1981. Their tattoos are roughly 1,000 years old and display ornate geometric designs, reminiscent of scales or vines, as well as an amorphous animal with a curled tail.
The Chancay have long been known for high levels of craftsmanship across their material culture, and left elaborate markings in far more than their tattoos, said Aaron Deter-Wolf, a prehistoric archaeologist at the Tennessee Division of Archaeology who specializes in ancient tattoos and was not involved in the study.
Dr. Pittman, a dinosaur paleobiologist, has spent more than a decade probing fossils with laser-stimulated fluorescence. This noninvasive tool exposes specimens to high-powered lasers, producing a fluorescent glow that sometimes reveals subtle features, like soft tissues. In recent years, Dr. Pittman’s team has started exploring the archaeological applications of the technique.
“We expect L.S.F. to work on other ancient tattoos from different cultures around the world and have plans to continue this imaging work to uncover similarly exciting discoveries,” Dr. Pittman said. “Hopefully we can push back the complexity of ancient tattoos even further back in time.”
Mr. Deter-Wolf was not convinced that the study demonstrated clear advantages of L.S.F. over other techniques for scrutinizing ancient tattoos, such as multispectral imaging. “This is a cool additional tool in our kit, but it’s not groundbreaking,” he said.
He also had concerns about some of the study’s conclusions. Dr. Pittman’s team suggested in the study that the tattoo patterns were made from punctures by a fine instrument, like a cactus needle or sharpened animal bone. Mr. Deter-Wolf believes that most tattoos examined in the study were made with incisions, not punctures.
“A painter uses different paintbrushes to achieve different results,” Mr. Deter-Wolf said. “Tattooists have done that same thing for thousands of years, so depending on the tool that they’re using, you will get a different physical signature as a result.”
Dr. Pittman stood by his team’s conclusion that the tattoos were made by puncture. “The unique thinness of our tattoo lines among published Chancay tattoos suggests a needle-based production (puncture tattooing) is more reasonable,” he said in an email.
Pinning down the methods that tattooists used is an important step in interpreting the meaning of body art to past societies. A range of techniques were used across cultures, and the process of making body art was often imbued with ritual significance.
For instance, Ötzi, a 5,300-year old “Iceman” with the oldest known body art on a mummy, may have been inked primarily for therapeutic reasons, rather than just aesthetics. While it’s natural to wonder why the Chancay took such pains with their work, their motivations remain a mystery.
“These are not purely artistic expressions,” Mr. Deter-Wolf said. “They are very culturally loaded.” The tattoo is the tip of the iceberg, he noted, but “there’s this whole cultural framework that underlies it.”.
