Indigo, the blue dye used in modern times to make the first blue jeans, may have been associated with ordinary folk in ancient Peru as well. Archaeologists led by Tom Dillehay of Vanderbilt University discovered textiles at the Huaca Prieta mound that date from as far back as 5,800 years ago and, after being washed by conservators, revealed a blue tint. Laboratory tests confirm the coloring is indigo, a dye made from the leaves of a shrub of the pea family, says Jeff Splitstoser of George Washington University, a textile specialist who conducted the tests with Jan Wouters of University College London. It is the oldest known use of indigo in the world, he says. “Blue from sources other than indigo is rare, so it has always been assumed it was indigo, but until now we never had the proof.” Huaca Prieta has been notable for its lack of high-class goods, a pattern that extends to indigo-dyed fabric, too, according to Dillehay. “I don’t see its early use associated with elites or high-status people,” he says. “In fact there is no evidence of artifacts or contexts of high-status people at Huaca Prieta. The data suggest egalitarianism.”

There are fancy obsidian blades from Mesoamerica and deftly knapped Clovis points, but many stone tools look, to the uninitiated, like … well … rocks. This is especially true of some of the simplest, oldest human-made artifacts. But there are reasons that a paleoanthropologist can pick up a seemingly random rock and say, “This was made by human hands.” There’s more or less no known natural mechanism that breaks certain kinds of rocks in a way that makes sharp edges, or knocks consistent flakes off a larger core. Spot those useful edges or flakes, and you almost certainly have an intentionally made tool. However, according to new research, that’s no longer strictly true, thanks to some bearded capuchin monkeys in northeast Brazil.

Researchers from the University of Oxford’s Primate Archaeology Research Group and the University of São Paulo recently found that these monkeys actually create “artifacts” that could be mistaken for human-made stone tools. The monkeys smack rocks together, for reasons that aren’t clear, but may involve licking the broken surfaces for silicon, an essential trace nutrient. Sometimes the rocks break in ways that create flakes or leave the broken rocks with sharp edges suitable for cutting or scraping. The monkeys don’t use them that way, but the researchers wrote that “the production of archaeologically identifiable flakes and cores, as currently defined, is no longer unique to the human lineage.”

Royal Alberta Museum archaeologist Bob Dawe recently returned to the scene of an unusual discovery he made in 1990. While excavating at Head-Smashed-In, a prehistoric buffalo jump in the foothills of the Rocky Mountains, he uncovered an intact 1,600-year-old sandstone-lined roasting pit. Such archaeological features are often found near buffalo jumps and were probably used to cook large quantities of meat for celebratory feasts—but they are always empty. This example was brimming with bones belonging to a buffalo calf, at least two adult buffalo, and a canine, probably a dog-wolf hybrid. The people who had hoped to dine on the meat, likely ancestors of today’s Blackfoot, never retrieved it. Sensing excavation of the pit would be a complicated affair, Dawe covered it up and vowed to return when he had the time to investigate it properly.

Last summer, with the help of paleontologists, Dawe and his team dug around the roasting pit and encased it in a plaster jacket so they could lift it out of the earth intact. Dawe plans to methodically excavate the feature in the laboratory, and eventually put it on display, but he doesn’t expect to ever find out just why the lavish banquet remained in the ground. “It would have been quite a feast,” says Dawe, “so something drastic must have happened. Maybe there was a blizzard, or a prairie fire. Or maybe other people drove them away.”