Adult wild long-tailed monkeys were found to be intelligent enough to understand which items had the highest value to visitors, such as an electronic object, and only release them after receiving food that they thought was of equivalent value. .
The authors said that the behavior displayed ‘unprecedented economic decision-making processes’ among the monkeys observed as part of the study.
An understanding of economics
Scientists from the University of Lethbridge, Canada and Udayana University, Indonesia, noted that, as well as the ability to ‘use objects as symbolic tools to claim specific food rewards’, the ability of monkeys to successfully exchange with age increased. an experience.
The research, published Monday, was conducted from 2015 to 2016 for 273 days, with further observations made in 2019.
The scientists filmed the monkeys as they stared at a visitor, approached them conspicuously, took an object and then stepped aside and waited for a suitable offer.
The adult monkeys “collected several food rewards before returning the token”, where the item was of great value, and “more likely” to accept a “less preferred food reward” in exchange for a lower value, the study said.
“Token robbery and sign / reward exchanges are cognitively challenging tasks for the Uluwatu macaque that have revealed unprecedented economic decision-making processes,” the authors said.
“This spontaneous, population-specific, general, cross-generation, learned and socially influenced practice could be the first example of a culture-sustained economy in free-ranging animals.”