Monkeys may have made stone artefacts thought to be humans’ earliest tools !!

Sarah Knapton 

Source - Monkeys may have made stone artefacts thought to be humans’ earliest tools (

Aa18tx5nA Burmese long-tailed macaque using a stone tool to open oysters in Thailand - Alamy© Alamy

Stone shards which were thought to be early tools made by our human ancestors can be created accidentally by monkeys, scientists have discovered.

Sharp flakes, dating back 3.3 million years, have often been found near the remains of ancient hominids, leading experts to believe they had been intentionally created by our forebears.

But a new study of long-tailed macaques in the Phang Nga National Park in Thailand showed that when they use rocks to crack open nuts, pieces of stone can shear off, leaving shards identical to those seen at hominid sites.

It opens up the question of whether early hominids were making the tools consciously, or whether they were simply a byproduct of other activities, such as nut cracking.

Some ancient stone tool finds which are not directly linked to hominid remains may even have been made by monkeys, the research suggests

Aa18tn3hExamples of sharp edged flakes produced unintentionally by long-tailed macaques - Proffitt et al© Provided by The Telegraph

“The ability to intentionally make sharp stone flakes is seen as a crucial point in the evolution of hominins, and understanding how and when this occurred is a huge question that is typically investigated through the study of past artefacts and fossils,” said lead author Tomos Proffitt, a researcher at the Max Planck Institute for Evolutionary Anthropology.

“Our study shows that stone tool production is not unique to humans and our ancestors.

“The fact that these macaques use stone tools to process nuts is not surprising as they also use tools to gain access to various shellfish as well.

“What is interesting is that, in doing so, they accidently produce a substantial archaeological record of their own that is partly indistinguishable from some hominin artefacts.”

Long-tailed macaques use stone tools to crack open hard-shelled nuts. In that process, the monkeys often break their hammerstones and anvils.

The resemblance of some tools used by primates to early hominid tools has led many experts to speculate that similar behaviour could have inspired intentional tool production.

In the new study, the team analysed 1,119 artefacts from 40 macaque nut-cracking locations on Ya Noi Island in Lobi Bay, Thailand, that resembled different stone flakes, fragments, hammerstones, and anvils.

Experts found that after cracking nuts the resulting detritus of broken stones bore all of the same characteristics that are commonly used to identify intentionally made stone tools at some of the earliest archaeological sites in East Africa.

Aa18tryeA long-tailed macaque using a stone tool to access food - Lydia V. Luncz© Provided by The Telegraph

The findings also give clues as to how stone tool use began in our ancestors.

Hominids may have also produced the sharp flakes accidentally while cracking nuts, before realising they could be useful as cutting implements, and in later years, arrow heads.

The flakes were thought to represent a turning point in human evolution because they demonstrated a level of planning, cognition and hand manipulation that could not be achieved by other animals.

But the new research suggests that flakes can be made without any such foresight.

“Cracking nuts using stone hammers and anvils, similar to what some primates do today, has been suggested by some as a possible precursor to intentional stone tool production,” said Lydia Luncz, senior author of the study and head of the Technological Primates Research Group at the Max Planck Institute for Evolutionary Anthropology.

“This study opens the door to being able to identify such an archaeological signature in the future and shows how living primates can help researchers investigate the origin and evolution of tool use in our own lineage”

Jonathan Reeves, co-lead author, added: “The fact that these artefacts can be produced through nut cracking has implications for the range of behaviours we associate with sharp edged flakes in the archaeological record.”

The research was published in the journal Science Advances.