Balinese macaques who understand economics

   Bali is a famous tourist destination in Indonesia. At the southernmost point of the island is the beautiful Uluwatu Temple, where a group of local Balinese macaques live. Local residents regard Bali macaques as sacred creatures. Not only can they freely enter and exit the temple, but they can also wander in the scenic spot at will, as if they are also visiting. But you must not be deceived by their innocent appearance. These Bali macaques are not here to relax. They are seriously searching for their prey: when they see their favorite item, they will suddenly rush out, taking advantage of it. The tourists were unprepared and robbed them directly from their bodies or hands, and the movements were astonishingly fast. Balinese macaques grab various items, including hats, hairpins, scarves, glasses, mobile phones, wallets, cameras, slippers…
   Most of these items cannot be eaten, so what do Balinese macaques do? Scholars from Lethbridge University in Canada and Udayana University in Indonesia have studied this phenomenon.
   The researchers observed the “robbing” behavior of 348 Bali macaques for 273 days, and found that through decades of iterative learning, the Bali macaques had already understood certain economic principles and experienced unprecedented levels of “robbing”. Economic decision-making process.
   Researchers found that after grabbing the item, the Bali macaque will implement the first step of its plan: run to a safer place nearby and sit down, just like a vendor waiting for a customer, waiting for the owner of the item to come and ask for it. In the process, they sometimes pretend to bite objects, as if they are threatening tourists: “If you don’t come quickly, things will be bitten by me.”
   If tourists want to get their things back, they will enter Bali. The second step of the macaque project: visitors need to exchange food with Bali macaques. Surprisingly, during this process, the Bali macaques exhibited a deep economic behavior of “getting it for sale”: when they think the price of the item they rob is low, tourists only need to take out a small amount of simple food. Redeem their own items; when they snatch higher-value items, if they redeem them with food they don’t like, they will simply refuse.
   When the Balinese macaques get the food they are satisfied with, things will enter the third step of the plan: the Balinese macaques will keep the objects in place and leave. In this process, it will not deliberately destroy items, and it can also ensure that visitors can get their own things back intact, as if they understand the truth of “theft is also right”.
   Through the observation and analysis of 1084 “robbings”, the researchers found that the snatch success rate of young Bali macaques was only 39.1%, and the snatch success rate of sub-adult and adult Bali macaques was as high as 61.5% and 68.8% respectively; young Balinese macaques grab everything, while sub-adult and adult Balinese macaques prefer to grab high-value items. The successful rate of “blackmailing” young Bali macaques, sub-adult Bali macaques and adult Bali macaques was 72.4%, 89.4% and 92% respectively, which means that as the age grows, Bali macaques learn more knowledge .