These monkeys steal big ticket items to trade for better food

Some of you may be familiar with the long tailed macaque monkey crime ring who reside around Uluwatu Temple in Bali, Indonesia, who were plunged into infamy a few years ago for robbing tourists and holding the ransom until they were paid in food. As if that visual weren’t stunning enough, a new study has found that some of the monkeys intentionally steal items that are most popular with humans in order to get the best bounty.

Carried out by researchers at the University of Lethbridge in Canada and Udayana University in Indonesia, the study found that monkeys carried out “unprecedented economic decision-making processes” when they stole things and held them for ransom. . The researchers said the practice – which has also been analyzed in similar studies with captive lab monkeys – is population-specific, widespread, intergenerational, scholarly and socially influenced. This is perhaps the first example of a culturally maintained symbolic economy in free-range animals, they wrote.

The study was published last week in the Philosophical Transactions of the Royal Society B newspaper.

However, not all monkeys fly at the same level. Researchers have found that age plays a role in this process, with older monkeys stealing objects more valued by humans. (The study literally called adult monkeys “the most skilled thieves.”)

“[T]he is more skilled [sic] and selective individuals appeared to make economic decisions, as evidenced by the clear behavioral associations between token possession based on value and the quantity or quality of rejected and accepted food rewards, ”the authors wrote.

To get to the bottom of this monkey case, the researchers analyzed 333 monkeys in the wild for 273 days from September 2015 to August 2016. An additional set of 15 monkeys were analyzed in December 2019. Observational data was collected by Video recording of the monkeys staring at potential human targets and standing about 16 feet (five meters) away. Human targets were defined as temple visitors carrying or carrying at least one inedible item that was “more or less likely” to be exchanged for food if stolen, according to the study.

He grouped the types of “tokens” targeted by the monkeys into six groups: empty containers (phone cases and camera bags); accessories (hairpins and key rings); hats (headgear and caps); shoes (flip-flops, sandals with heels); glasses (glasses and sunglasses); and electronic devices and wallets (cell phones, cameras and handbags). The researchers then categorized these items into groups of low-value tokens, medium-value tokens, and high-value tokens based on how often humans wanted to trade with apes for them.

Low-value tokens like empty containers and accessories were rarely traded by humans, according to the study. Medium value tokens, like hats and shoes, were often exchanged for. While high value tokens, like eyeglasses, electronics, and wallets, were almost always traded by humans.

Let’s go back to the age. According to the study, monkeys were much more likely to be successful at stealing a coveted item the older they were. Subadult monkeys did better than juveniles, while adults did better than subadults and juveniles. But it’s one thing to steal something, it’s another to trade and get rewarded for it. In this aspect, adults and subadults again came out above, while juveniles finished last.

With age comes wisdom, or more precisely, in this case, the ability to differentiate between low, medium and high value tokens. The study found that juvenile monkeys didn’t really care what types of items they managed to get their hands on, but subadult and adult monkeys preferred high-value tokens over low-value, or valuable tokens. medium to low value tokens.

Finally, the researchers decided to look at the “most skillful [sic] and selective individuals ”, or subadult and adult monkeys. In terms of quantity, both groups of monkeys waited until they were offered more food rewards before returning the item when they felt it was of great value. However, adult monkeys were even more picky about quality and rejected more of their less preferred types of food rewards when they held an item of greater value.

Talk about being a tough negotiator.

Dr Jean-Baptiste Leca, lead author of the study and associate professor of psychology at the University of Lethbridge, said the Guardian that theft and barter are an expression of the cultural intelligence of apes.

“These behaviors are socially acquired and have been maintained across generations of monkeys for at least 30 years in this population,” he said.

Ultimately, this study was a fascinating look at the brains of these petty thieves. It also reminds me of something a bunch of criminals would do in a Netflix series. I would watch that.