Scientists discovered that capuchin monkeys used tools for more than 700 years. Hitting one rock against another may not be just playing around, as it seems that the primates learned learned centuries ago how to extract cashew nuts.
A new study shows that the capuchin monkeys are hitting rocks to crack open cashew nuts, which they consider to be a special treat. It also seems that the technique had been put into place centuries ago. The monkeys transmitted the practice from one generation to another.
Archaeological records showed the scientists that the tools used by the primates were invented almost 700 years ago. The evolutionary biologists say that the discovery marks the first documented tool used by non-great-apes.
The cashew nuts are covered in a double shell that contains an allergenic resin, an anacardic acid, and a toxin that is also found in the poison ivy.
The primates discovered a system of two rocks that works just like a hammer and an anvil. The monkeys place the fruit on a flat rock and hammer it until they are able to retrieve the seed.
The Anvil System Used by the Capuchin Monkeys
The researchers monitored the activity and reached the conclusion that the capuchins are not randomly hitting rocks, they are carefully choosing their tools, and they adjust the hammering in order to be as efficient as possible.
It also seems that monkeys need years to perfect the practice. They learn how to do it properly, and it is not something that comes easily to a wild animal. The rock system is one of the first tools ever used by the monkeys. They don’t have enough experience in using them. In evolutionary terms, 700 years is not a very long time.
Moreover, the scientist discovered that the rock anvil system did not change a lot during the years. The primates did not try to bring any upgrades, as they still strive to learn the simple process. There is little creativity in their behavior, even if using tools is enormous step forward for the small primates.
The Food Quest and the Evolutionary Techniques
The capuchin monkeys have a quite diverse experience with tools. Sometimes, they use sticks to gather food, which is quite uncommon among neotropical primates.
In other parts of the world, other primates use the same technique. Among such animals, there are the chimpanzees from Western Africa or the Asian macaques. The scientists believe that the monkeys had to adapt when they had to look for new sources of food.
Finding rocks that had been used by the small animals centuries ago is one of the greatest accomplishments in the archaeology of wild things.
As the animals use sticks and other tools that are made of organic materials and degrade quickly, the scientists have no ontogenetic evidence on how the animals evolved over time.
The authors of the research hope that such proofs may shed some light on how life evolved on Earth and the studies will continue to explore the differences between species and their history.
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