Crows are spectacularly intelligent creatures. Previous studies have shown that a particularly perceptive corvid species, the New Caledonian crow, may even be smarter than a first-grader—at least when it comes to reasoning abilities. But a new report published in Scientific Reports suggests we’ve only begun to unlock the brainy birds’ true potential.
As Victoria Gill reports for BBC News, researchers from the University of Oxford and Germany’s Max Planck Institute for Ornithology have recorded video footage of New Caledonian crows assembling compound tools, a feat previously accomplished by just two other species: humans and chimpanzees.
To test the birds’ tool-making skills, the scientists designed a “puzzle box” that placed food just out of reach. Initially, Brooks Hays writes for UPI, the eight crows participating in the study were provided with long sticks capable of reaching and prodding the treat out of an opening in the box’s side.
All proved adept at the task, so the team moved on to a more difficult scenario, replacing the long sticks with an assortment of short cylindrical sticks, none of which were long enough to grab the treat on their own. The Financial Times’ Clive Cookson further notes that the sticks, some hollow and some solid, had slightly different diameters that enabled the crows to piece them together.
Incredibly, four of the eight birds discovered the key to solving the puzzle within just five minutes. By combining two of the shorter sticks, the crows were able to reach the food and push it out of an opening at the other end of the box. A crow named Mango actually created tools featuring three or four parts, offering, according to the study, “the first evidence of compound-tool construction with more than two elements in any non-human animal.”
Alex Kacelnik, a behavioral ecologist at Oxford and one of the study’s lead researchers, tells BBC News’ Gill the findings subvert the idea that animals “try everything at random and improve by reinforcement.” Instead, he argues that the crows, which received no demonstration or aid throughout the experiment, were able to predict the properties of a tool not yet in existence.
“So they can predict what something that does not yet exist would do if they made it,” Kacelnik explains. “Then they can make it and they can use it.”
According to Science Alert’s Michelle Starr, three of the four successful crows—Tumulte, Tabou and Jungle—managed to replicate their crafty compound tool-making in three subsequent trials. Mango, the New Caledonian crow who built three- and four-part tools, reportedly exhibited “fluctuating motivation,” refusing to participate in two follow-up trials but succeeding in later test runs.
The researchers write that Mango’s actions appear to represent a deliberate tool-making process rather than an accidental discovery.
Multi-compound tool construction requires “dexterity and perseverance,” the team explains, citing Mango’s persistence—Starr points out that the bird’s tools fell apart several times, but he always reconfigured them until they worked—as proof of the crows’ complex cognitive abilities.
For now, it remains unclear exactly how the animals solve problems with such skill and speed.
“It is possible that they use some form of virtual simulation of the problem, as if different potential actions were played in their brains until they figure out a viable solution, and then do it,” Kacelnik said in a statement. “Similar processes are being modelled on artificial intelligences and implemented in physical robots, as a way to better understand the animals and to discover ways to build machines able to reach autonomous creative solutions to novel problems.”