In Native American legends and in fairy tales, crows are often depicted as sly and crafty birds. And a new study published in the open-access journal PLOS One from the University of Aukland shows that these old legends and fairy tales contain an amazing truth, because according to researchers, crows are as good at reasoning as human seven-year-olds.
Scientists already were aware that New Caledonian crows are pretty clever and are known to make and use tools. For example, crows are able to use a stick to get something out of their reach and, in a pivotal 2002 experiment, a New Caledonian crow called Betty was seen bending some wire into a hook to snag her morsel of food.
Now, researchers are demonstrating just how smart these birds are. Inspired by Aesop’s fable “The Crow and the Pitcher,” researchers tested the ingenuity of New Caledonian crows.
That ancient fable, whose origins are lost in the mists of time, is about a thirsty crow who encounters a pitcher with water at the bottom, too far down for the crow to reach with his beak. After failing to push the pitcher over, the bird starts dropping pebbles one by one into the pitcher until the water was displaced and rose to the top of the pitcher. The moral: that ingenuity will serve you better than brute strength.
In the new study, the researchers devised a set of tasks in which six wild crows had to drop objects into tubes filled with water to get the yummy treat at the bottom, according to a report by Time. The crows were given a choice of objects to drop into the tube. Some of the objects were porous and floated on top of the water, so dropping them in the tube got the crow no closer to his treat.
Given a choice, the crows seemed to have some grasp of water displacement, as they quickly favored solid objects rather than porous ones. The result: the crows performed as well as children between five and seven.
The New Caledonian crow’s I.Q. has its limits, however. When faced with narrow and wide tubes, with more water in the wide one, the crows chose the wide tube. And when shown tubes with the same amount of water, they usually just dropped pebbles into one or the other tubes until they got their treat, not realizing that dropping pebbles into just one would get them to their goal more quickly.
These new findings compliment an ever-growing body of evidence showing that the minds of animals–even ones with itsy-bitsy brains–are far more complex than previously thought.