Some monkeys accidentally create stone flakes that resemble ancient hominid tools

Monkeys in southern Thailand use rocks to pound open oil palm nuts, inadvertently breaking off pieces of stone with their makeshift nutcrackers. The researchers say that these flakes resemble some of the sharp-edged stone tools believed to have been made by ancient hominids.

Thailand’s long-tailed macaque (macaque fascia) could easily be mistaken for stone flakes found at 17 East African hominid sites dating back to about 3.3 million to 1.56 million years ago, say archaeologist Tomos Proffitt and colleagues. search shows that Ancient hominids may have occasionally made stone flakes by mistake When using rocks to crack nuts, bones or other objects, scientists report on March 10 science advance,

previous research has already shown Rock-wild capuchin monkeys in Brazil inadvertently produce hominid-like stone flakes (Sn: 10/19/16,

Observations of rock bashing by these two monkey species undermine the long-standing belief that hominids may have intentionally created some ancient stone flakes, including Some of the earliest known examples of toolsProfit says (Sn: 6/3/19, It is time to re-evaluate how such determinations are made, he says.

Proffitt’s group identified 219 complete and fragmentary stone flakes at 40 macaque nut-cracking sites on the island where the monkeys lived. The team also found rocks showing damages that may have been either pounding implements or used as pounding platforms.

Some differences exist between macaque and hominid stone flakes, says Proffitt of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. For example, many macaque flakes display damage to only one side, compared to the frequent double-sided damage on hominid artifacts.

Such clues could help archaeologists develop guidelines for estimating whether ancient hominids made stone flakes on purpose or by accident, Profit suspects.