An old Aesop fable was recently used to test the intelligence of raccoons, with some interesting results.
The fable in question is The Crow and the Pitcher, in which a thirsty cow realizes it needs to add stones to a pitcher of water in order to raise the water level high enough that he can drink it. The idea has actually previously been used to test whether birds and small children understand cause and effect, to varying degrees of success.
As Phys.org reports, in the experiment, raccoons were given a tube filled with water with a floating marshmallow in it. Stones were placed on the tube’s rim, so when a raccoon accidentally knocked a stone into the tube, it raised the water level high enough for enough for it to access the marshmallow.
Later, after the above “training” sessions, researched attempted to see if the raccoons could remember what they’d learned. Of the seven raccoons that participated in the experiment, two were able to figure out that picking up a nearby stone and dropping it into the water equaled getting the treat.
It’s not quite proof that raccoons can understand water displacement and what was happening in the experiment, but it is encouraging evidence that the raccoons are potentially able to cognitively solve problems.