Aesop’s Rook
Scientists at Cambridge University have just published findings that suggest one of Aesop’s fables could really be true. A thirsty crow drops stones into a vessel to raise the water level enough to get a drink. Christopher Bird and Nathan Emery performed an experiment using four captive rooks, using a floating worm to tempt the rooks to drop stones into the vessel.
All four rooks solved the problem, and showed an appreciation of the number of stones required. They also learned to pick larger stones over smaller ones, and that the same trick wouldn’t work with a worm floating on sawdust. The details are available at sciencedirect.com.