A thirsty crow (乌鸦) comes across a bottle of water, but the water is out of reach. The bird then drops some stones into it until the water level rises (上升) within its reach and it starts drinking.
"It's just a story," you may think. However, a new research has found that crows may be sometimes smarter than 6-year-old children.
In a recent experiment (实验), American scientists Corina Logan and her team caught six crows to test them. The crows and children had to choose between two kinds of tubes (管子)—a red one or a blue one. Both children and crows had to drop in stones to reach the water.
When they dropped a stone into the red tube, the water level rose in a connected (连接的) bottle. The blue tube, however, had nothing to do with the rise or fall of the water level in the connected bottle. Children aged 7 to 10 were able to find out the rule quickly. But children aged 4 to 6 failed. Five of the six crows failed the test. But Kitty, a 6-month-old crow, passed it. She put most of the stones into the red tube.
So, could a bird be cleverer than a kindergartner? Don't be too quick to say no.