The Uluwatu Temple in Bali, Indonesia is plagued by brazen thieves who sneak up on tourists and make off with anything their sticky fingers can grab: sunglasses, hats, cameras, flip-flops. As Brian Owens reports in New Scientist, these pilfering menaces are not your average human criminal—they are long-tailed macaques.
The monkeys will only relinquish their ill-gotten gains after members of the temple’s staff offer them tasty treats. Thanks to numerous YouTube clips, you can watch these little terrors carry out their scheme. In one video, a macaque sits with a firm grip on a pair of glasses while people try to tempt it with a parade of different snacks. The monkey chucks each offering on to the ground until a nice piece of fruit tickles its fancy. It then lets go of the glasses and munches on the fruit.
This behavior, which has only been reported among macaques of the Uluwatu Temple, was the subject of a recent study published in the journal Primate. A research team led by Fany Brotcorne, a primatologist at the University of Liège in Belgium, observed four different groups of monkeys over the course of four months in 2010. The scientists hoped to learn more about how and why the crafty creatures developed their signature “robbing and bartering” system.
According to Rae Paoletta of Gizmodo, the team observed 201 instances of robbing and bartering. The authors of the study write that the theft “usually occurs in two steps: after taking inedible objects (e.g., glasses) from humans, the macaques appear to use them as tokens, returning them to humans in exchange for food.”
Groups that spent the most time near tourists displayed higher rates of this behavior, leading Brotcorne to conclude that robbing and bartering is a “cultural tradition”—a trait that the Uluwatu Temple monkeys learn from one another, and transmit to successive generations.
Brotcorne told Owens that her research offers insight into how primates plan, understand their own actions, and transmit information between groups. A new development has, in fact, bolstered Brotcorne’s theory that “robbing and bartering” is a learned behavior. A fifth group of macaques recently moved into the area, and its members have since started to torment tourists in the hope of scoring snacks.
So visitors to the Uluwatu Temple, take note: hold onto your hats (and sunglasses, and shoes, and cameras).