Ravens can plan ahead and barter for food
The clever corvids show cognitive abilities that were believed to exist only in primates, according to a new study.
Humans – most of us, at least – can plan ahead. So can chimpanzees. But ravens? A new behavioural study shows that primates are not the only animals capable of thinking of the future.
In research published in Science, Can Kabadayi and Mathias Osvath of Lund University in Sweden put ravens in different scenarios in which they could profit by demonstrating higher reasoning skills like patience, the ability to use tools, and the ability to plan ahead.
The ravens were consistently successful in these tests and demonstrated complex behaviours such as sacrificing a small immediate reward to obtain a larger one later.
While corvids, the family of birds that includes ravens, crows and magpies among others, have in the past been seen to cache food for the future, this research looked for signs of more complex forward planning.
The ravens were taught to open a box with a tool to access a reward. They ravens were then presented with the box, but not the tool. The box was removed and one hour later the ravens were given the opening tool, as well as several “distractors”. Nearly every raven chose the tool that would open the box, even though the box was no longer present. When the box was returned, 15 minutes later, 86% of the birds successfully used the tool to open it.
A similar result was observed in an experiment where the ravens exchanged a token with a human for food. The study reports that the ravens did a better job than apes at planning for the token task, and about as well as apes for the tool-handling task.
Later again, the birds were given a choice between the box-opening tool (or the food token), distractors, and an immediate reward. They chose the tool or token, which would allow them to obtain a greater reward later, about three quarters of the time.
This shows that the ravens have a level of self-control similar to that seen in primates.
“Ravens are not habitual tool users, and bartering has never been observed in the wild,” the researchers write. “The experiments were mainly chosen because they replicate key experiments with primates.”
The results indicate that ravens have a general-purpose ability to adapt to new circumstances and conceive of the future in some way.
It has been more than 300 million years since the birds have shared a common ancestor with humans or great apes, which suggests that their ability to plan evolved independently of ours.