Ravens have proven themselves capable of planning ahead, according to new research published this week in the journal Science that demonstrated that these members of the corvid family could be trained to stash away a tool that they would need to use later while still in the wild.
Thinking ahead was once believed to be a uniquely human trait, but in recent years, experts have found that some adult great apes are also capable of pre-planning. Now, two cognitive zoologists from Lund University in Sweden have established that ravens possess a similar aptitude.
The zoologists, Can Kabadayi and Mathias Osvath, conducted a series of experiments to find out if a group of ravens could flexibly plan to use tools and barter with each other – tasks which they typically do not perform, but which are similar to those used to evaluate a great ape’s aptitude for planning ahead, according to NPR and New Scientist.
In one experiment, the ravens were trained to open a box that contained a piece of dry dog food by dropping a stone through a small tube. Then, after a short delay, the birds were shown several different objects without the reward box to see if they could select the correct item, and then save it for future use.
Initially, there was a 15 minute delay between the ravens’ selection of the object and the return of the reward box, and during this experiment, the ravens succeeded 86% of the time. Later, the researchers increased that wait time to 17 hours, but the success rate went up, not down – in fact, the birds succeeded at the task 88% of the time, according to NPR.
Findings suggest that the trait evolved independently in corvids
In another experiment, the birds participated in a bartering test, said New Scientist. Once again, they received training on how to use an object, but this time, they had to exchange said item for a reward. Afterwards, they had to select the correct item, hold onto it for 15 minutes, and the trade it with one of the researchers for a reward.
They succeeded nearly 77% of the time, so Kabadayi and Osvath once again increased the delay between the selection of the tool and its use to 17 hours, and once again, the ravens’ success rate went up. Despite the lengthy delay, the birds succeeded nearly nine out of every 10 times.
Based on the results of these experiments, the researchers wrote, “It is conservative to conclude that ravens perform similarly to great apes and young children” – and, it should be noted, better than monkeys, who have failed similar experiments in the past, according to NPR. Furthermore, they told New Scientist, the birds were clearly planning ahead from the first experiment onward, indicating that this was not merely a case of habituation.
The research shows that “ravens plan for events unrelated to caching – tool-use and bartering – with delays of up to 17 hours, exert self-control, and consider temporal distance to future events. Their performance parallels that seen in apes and suggests that planning evolved independently in corvids, which opens new avenues for the study of cognitive evolution,” the authors wrote.
Image credit: Unsplash/Tyler Quiring