Raccoons pass an ancient intelligence test by knocking it over

In what could be considered the ultimate ‘thug life’ moment, a raccoon knocked over a tall tube of water during a scientific experiment designed to test its understanding of basic science.

But this act of vandalism was successful: the animal has completed an ancient test of intelligence in an innovative new way, but researchers are unsure whether she really passed it or not.

The test, called ‘The Crow and the Pitcher’ is an ancient Greek fable, used to study an animal’s understanding of cause and effect. It’s been used on birds and children, and involves a pitcher of water and a thirsty participant, or a floating treat.

Those taking the test have to understand the way water displacement works; by dropping stones into the pitcher, the water level will be raised high enough so they can drink it. Crows have passed the test in the past, but a new paper used the fable to test raccoons for the first time.

Researchers from the University of Wyoming tested eight raccoons using a pitcher of water with marshmallows floating on top, to see whether they would drop stones in the water to allow them to reach the marshmallows. None of the raccoons spontaneously knew to place stones in the pitcher, and a few were able to learn from training that this is how to pass the test.

But another, extremely innovative, raccoon had a new way to get to the marshmallows. She just pushed it over – no mean feat, given how heavy it was. Birds have never done this.

“We found raccoons to be innovative in many aspects of this task, and we observed diverse, investigative behaviours that are unique to raccoons,” says Lauren Stanton, lead author of the paper. 

The team said in the paper that the raccoons might not seek out the most logical option because they are happy to explore. This is because in the wild, they need to explore to survive.

The experiment itself might have played a role too. The raccoons had fewer opportunities to interact with the puzzle than many of the birds tested in previous studies. This means, the raccoons might get better at it if they have more time to familiarise themselves with the stones and the water tube.