To the untrained ear monkeys of a certain species may all sound the same, but Japanese researchers have found that, like human beings, they actually have an accent depending on where they live.

The finding, the first of its kind, will appear in the December edition of a German scientific journal Ethology to be published on December 5, the primate¹ researchers said Tuesday.

"Differences between chattering² by monkeys are like dialects of human beings," said Nobuo Masataka, professor of ethology at Kyoto University's Primate Research Institute.

The research team analyzed³ voice tones of two groups of the same species of primates⁴, the Japanese Yakushima macaque also known as Macaca fuscata yakui, between 1990 and 2000.

One group was formed by 23 monkeys living on the southern Japanese island of Yakushima, and the other group comprised 30 descendants from the same tribe moved from the island to Mount Ohira, central Japan, in 1956.

The result showed that the island group had a tone about 110 hertz higher on average than the one taken to central Japan.

Monkeys on Yakushima Island have an accent with a higher tone because tall trees on the island tend to block their voice, Masataka said.

"On the other hand, monkeys on Mount Ohira do not have to gibber with a high tone as trees there are low," he said. "Each group adopted their own accent depending upon their environment."

This suggests differences in voice tones are not caused by genes⁵, Masataka said, addi ng the results "may lead to a clue to the origin of human language." 

　　中文：

　　普通人听来，某种猴子的叫声都是一样的。但日本研究人员发现，其实跟人一样，它们栖息在不同的地区，其口音也不相同。

　　据法新社11月29日报道，1990年到2000年，日本一个研究小组对两群日本猕猴的口音进行了跟踪研究。参与研究的日本京都大学灵长类动物研究中心的生态学教授Nobuo Masataka说：“猴子口音之间的差异，就跟人类有不同的方言一样。”其中一群猕猴有23只，栖息在日本九州岛以南的屋久岛上；另一群猕猴共30只，它们的父辈1956年时从屋久岛迁移到了日本中部的大平山。研究结果表明，留在岛上栖息的猴子的平均声调比迁移到大平山的猴子的平均声调要高110赫兹。

　　Nobuo Masataka认为，岛上生长的高大树木阻挡了声音的传播，使得猴子不得不提高调门。因此，岛上猴子的声调要比大平山的猴子的声调高一些。“大平山地区的树木较矮，栖息在那里的猴子不需要高声叫喊，”他说，“各个猴群都根据所处的环境选择了不同的口音。”

　　Nobuo Masataka说，这一发现表明，猴子声调的不同并不取决于基因，这可能将为科学家探索人类语言起源提供新的线索。

　　这项研究刊登在12月5日出版的德国科学杂志《生态学》上。