Uganda

In Uganda, a newly arrived female chimpanzee showed the others how to dig wells in sand.

Her name was Onyofi, and she came from another group. Shortly after moving in, she began digging small holes in the sand beside a water hole. She waited while the water seeped in, and drank.

The strange thing was that the water hole was right there. She could have drunk from it directly. Researchers think she dug because the sand filters the water and makes it cleaner.

The others watched. Big, dominant males waited until she’d drunk, then drank from her well themselves. Soon more females were digging their own in the sand.