Burmese Long-Tailed Macaques in Danger: Tool-Using Behavior May Disappear

Burmese long-tailed macaques are smart for monkeys. They use stone tools in order to crack open the hard shells of invertebrates, such as rock oysters, sea snails and crabs. Now, though, this lifestyle may be threatened. It turns out that human farming and the introduction of domestic dogs are posing a threat to a macaques' ability to use these stone tools.

The Burmese long-tailed macaque is a very rare species of the common long-tailed macaque. It's only found in Myanmar and the bordering areas of Thailand. In order to understand a little bit more about this monkey and how human populations might be affecting this rare animal, researchers examined macaques within the Laem Son National Park on Piak Nam Yai Island.

So what did the researchers find? It turns out that the island's macaque populations consisted of 192 individuals that were divided into nine social groups. Of these individuals, 88 percent of all adults used stone tools. This seemed to indicate that tool-use was part of the everyday life of these macaques, which means that anything hindering that use would drastically impact the population.

So what interferes in this tool use? It turns out that of highest concern is the illegal development of rubber farms and oil palm plantations, which clear portions of forest. In addition, humans compete with the macaques for food by harvesting bivalves. Another major concern is harassment by domestic dogs that have been released to protect farms. These dogs repel macaques from the shores, which inhibit their tool-using activity.

"These Burmese macaques are the only monkeys in Asia that use stone tools," said Michael Gumert, one of the researchers, in a news release. "Only two other primate species out of the several hundred in the world use stone tools--the chimpanzees in Africa and the capuchin monkeys in South America. Knowing about primate stone tool use has important implications to compare with early hominine tool use, as well as the origins of cultural behavior. Studying traditions allow us to investigate the cultural capacity of animals."

Currently, the researchers hope to develop a long-term program on these tool-using long-tailed macaques. The future research could help to conserve these animals and their unusual behavior.

The findings are published in the journal Oryx.