Scientists tested raccoons with a nine-way puzzle they kept solving after food was gone

Raccoons have long been credited with outwitting latches, and a study has tested that reputation. University of British Columbia researchers Hannah Griebling and Dr Sarah Benson-Amram gave captive raccoons a custom puzzle box with nine entry points, grouped as easy, medium and hard. Each 20-minute trial held a single marshmallow; the raccoons often kept opening new mechanisms after eating it. Sixteen adult raccoons were tested in Colorado, and fourteen completed all three difficulty levels. The authors call the behaviour information foraging, and the paper reports that all but one raccoon solved multiple solutions within single trials.How did scientists test raccoons with a nine-way puzzleAccording to the University of British Columbia news release, the researchers used a custom multi-access puzzle box with mechanisms such as latches, sliding doors and knobs. The box had nine entry points, grouped as easy, medium and hard. The paper states that the box was a Plexiglas cube measuring 25.4 centimetres on each side, with removable panels. One panel was plain Plexiglas, and the other three held solutions that gave access to the food in the centre, so each raccoon faced three solutions ...