Throughout the history of Earth, humans and their primate relatives are believed to be the only animals that create and use stone tools, according to archaeological records.
This era is known as the Stone Age – a prehistoric period lasting nearly 3.4 million years and ending around 8700 BC to 2000 BC, coinciding with the advent of metal tools. During this period, stone was widely used to create tools with sharp edges, pointed ends, or one flat side for pounding. Stone tools were made from various types of stones. For example, flint and chert were sharpened (or chipped) to create cutting tools and weapons, while basalt and sandstone were used for implements like grinding stones.
With the advantage of tools, along with superior intelligence and population, humans ascended to the top of the food chain. Animals that once considered humans prey or were large enough to threaten our ancestors eventually had to submit. It can be said that learning to use stone tools marked the beginning of human intelligence.
However, recent discoveries suggest that the number of animal species capable of creating stone tools during the Stone Age is greater than previously thought.
Primate Species in the Stone Age
Chimpanzees (Pan troglodytes) have used stone tools like hammers and anvils for millennia. According to a study published in 2007 in the Proceedings of the National Academy of Sciences, chimpanzees in Côte d’Ivoire used these tools as far back as 4,300 years ago.
Thus, the Stone Age for chimpanzees predates the emergence of farming villages, where humans settled in tropical regions of Africa.
Capuchin monkeys are in their own “Stone Age,” as they have been observed using stones as tools. This is a Capuchin monkey using a stone to crack open a coconut. Photo: Dorit Bar-Zakay / Getty Images
Capuchin monkeys (Sapajus libidinosus) in Brazil have also used stone tools to crush nuts for the past 3,000 years. Findings published in Nature Ecology and Evolution indicate that the shapes of their stone tools have evolved over millennia to accommodate different types of food.
Meanwhile, a group of researchers found stone tools used by long-tailed macaques (Macaca fascicularis aurea) to open shells on a beach in Thailand. These tools may have been used from 1950 to 2004.
Overall, despite the relatively crude appearance, a stone hammer made by a chimpanzee cannot compete with the craftsmanship of a human-made hand axe. But that is not the point. These primates have developed a culture of regularly using stone tools. This means they have entered the Stone Age.
Why Do Primate Species Use Stone Tools?
At this time, researchers are still unclear on why these primate species have learned to use stone tools. In each primate species, tool use is considered a social behavior learned from their parents and other members of the group.
In the case of chimpanzees, primitive stone tools indicate that their behaviors were inherited from a common ancestor of both humans and chimpanzees. However, it is also possible that humans and chimpanzees have independently learned to use stone tools. The same can be said for other animals that use stone tools.
These primate species have developed a culture of regularly using stone tools, signifying their entry into the Stone Age.
Interestingly, different primate groups use different types of stone tools. For example, some groups of chimpanzees use a stone hammer to crush nuts, which are placed on a stone anvil.
It should also be noted that the fact that an animal species enters the “Stone Age” does not mean that it will soon follow the evolutionary and developmental trajectory of humans, as we have transitioned into the Bronze Age, Iron Age, and ultimately reached the Information Age in which we currently live.
This does not imply that animals that use stones as tools are smarter than others. Instead, other animal species may create similar tools from wood or leaves.
In the case of humans, although the term Stone Age is named after the remaining tools, we do not “only use stone as tools.”
“Stone Age” for other animal species is similar. For instance, chimpanzees use long pieces of bark to catch termites. They also use plants for medicinal purposes. In many cases, tools made from plants are actually more complex.
It is reported that after primates, researchers hope to shed light on the history of another animal species that uses stone tools: sea otters. Researchers have observed sea otters cracking open mussel shells on rocks. This implies that the number of species in the Stone Age will likely increase in the future.
