A group of Panamanian monkeys may have entered their own Stone Age, scientists said.

科学家们日前表示，一群巴拿马猴子可能已经进化到了它们自己的石器时代。

A population of white-face capuchin monkeys living on the Panamanian island of Jicarón have been observed using stones to smash open nuts and shellfish, New Scientist reported last Monday.

据《新科学家》上周一报道，一群生活在巴拿马岛的白脸卷尾猴被观察到用石头砸开了坚果和贝类。

Scientists first made the discovery in 2004, but returned to the island in March 2017 with cameras to catch the monkeys in the act.

科学家们在2004年首次发现了这一行为，而在2017年3月，他们带着相机回到岛上拍摄到了猴子的这种行为。

Scientists do not know when the 6 million-year inhabitants of the island began the practice, but believe the skill was learned "by chance." Scientists said the practice was only evident in a few males.

科学家们不知道在岛上生活了600万年的猴子是什么时候开始有这样的行为的，但他们相信这项技能是“偶然”学会的。科学家表示，这种行为只在少数雄猴身上体现出来。

No other nearby populations have been observed making use of stones, the report said.

该报告称，附近没有发现其他使用石头的种群。

The discovery marks the fourth observed group of non-human primates that have used stones for tools.

这一发现标志着将石头作为工具使用的第四种非人类灵长类动物被成功观察到。

Other species with similar practices include chimpanzees in West Africa, macaques in Thailand and other species of capuchins in South America, New Scientist reported.

据《新科学家》报道，其他有类似行为的物种还包括西非的黑猩猩、泰国的猕猴以及南美洲其他种类的卷尾猴。

Until a few decades ago, scientists believed humans were the only species that appropriated stones into tools. The Stone Age for humans began 2.5 million years ago.

直到几十年前，科学家们还认为人类是唯一将石头当做工具的物种。人类的石器时代始于250万年前。