Monkey See, Monkey Do: Transmission of Tool Use Across Primate Groups

Tool use by early humans (Image: Wikipedia)

 Human beings have long been associated with two things; the discovery of fire, and the widespread use of assistive tools. These two things may seem incredibly simple, but they were what propelled our species into new frontiers of progress.

However, scientists have since discovered that we were not the only animals that used our handedness to craft objects. In fact, many creatures are capable of meandering with their environment, and searching for raw materials to create new objects from scratch.

 Tailorbird's "pouched" nest and Woodpecker's twig use (Image: Stone Lodges/HBW Alive)

In birds, tool use is especially common and distinct across their own genus. Tailorbirds are known to manufacture pouches to make their nests in, while others such as weaver birds build incredibly sophisticated nests. However, one of the hallmarks of tool use in birds happen to be from woodpecker finches. These birds have outdone themselves by jabbing twigs into trees to catch larvae. Truly incredible birdbrains.

An octopus using coconut shells (Image: Pinterest)

In octopuses, tool use signify the first instance of an invertebrate acquiring tools for its own advantage. Most people already know that octopuses are perhaps some of the most intelligent animals on the planet that is capable of human-like cognition. However, recent discoveries in its ability to use tools may demonstrate that they have adaptive cognition as well.  They will readily use halved coconut shells discarded by humans as armors against predators, and even as highly portable shelters!

While these may truly be incredible feats of cognition displayed across the animal kingdom, nothing really matches up with primates.

Capuchin Monkeys "Nut-cracker" tool use (Image: New Scientist)

In a recent study, capuchin monkeys were found to be highly adaptive to their environments; showing the ability to be cerebral towards their environment. The study conducted by an international research team consisting of Institute of Cognitive Sciences and Technologies of the National Research Council (CNR)'s Elisabetta Visalberghi, University of Cambridge's Kathelijne Koops, and University of Zurich's Carel van Schaik discovered that South American capuchin monkeys can use basic stone tools to break open hard-shelled palm nuts for consumption.

Why did they exhibit such behavior? According to the researchers, it was because the capuchin monkeys studied were terrestrial - meaning they spend a lot of time on the ground, which gives them the opportunity to use the floor as anvils to craft tools. Likewise, capuchin monkeys that spend a lot of time on trees and above ground exhibited less tool-use behavior. Moreover, the availability of raw materials in their environment also encouraged the monkeys to craft and use assistive tools for their benefit.

Macaques flossing teeth (Image: BBC)

It was also reported that macaques, a species of Old World monkeys commonly found in Asia, was a rampant user of tools as well. The macaques residing around a Buddhist temple in Lopburi, Thailand were found with a habit of pulling out hairs from visitors to use as some sort of flossing to clean their teeth.

What's more incredible, is the demonstration of social transmission of knowledge across the primate lineage living in the temple. It was reported that the female macaques had a heritage of showing the young how to floss their teeth by slowing down and exaggerating the flossing motions.

Chimpanzees looking for army ants (Image: Britannica)

 In another example of tool use, West African chimpanzees in Guinea has been reported to have a preference for using the long, straight shoots of an Alchornea hirtella plant to hunt army ants. By using such a tool, they are avoiding their hands from getting bitten by the extremely aggressive eusocial insects. This is a powerful demonstration of problem-solving ability on the chimpanzee's part.

More interestingly, the chimpanzees would choose longer tools for faster and more aggressive army ants, and shorter tools for slower and less aggressive army ants. By showing preference in this way, we can say that they have strategic decision-making skills too.

However, the caveat is that scientists do not currently know whether this behavior is influenced entirely by genetics alone, or by the environment, or a combination of both. The researchers propose that the behavior is more cultural than just plain ole' gene/environment interaction. This is because - surprise - the tool use was socially transmitted through teaching by older chimpanzees to their young.

These are just some of the many examples that illustrate just how intuitive non-human primates are - and in many ways how they are similar to human beings. However, this blog post does not take into account the genetic implications leading to such behaviors. As such, that will be something that will be explored in future blog posts as I continue shredding through the various literature on the subject.