Not such a birdbrain Mathias Osvath/Lund University

Ravens can plan for future events at least as well as 4-year-old humans and some adult, non-human great apes.

The birds did this in tasks they wouldn’t encounter in the wild, so it isn’t an adaptation to an ecological niche, but rather a flexible cognitive ability that evolved independently in birds and hominids, whose lineages diverged about 320 million years ago.

Planning for future events requires the use of long-term memory for some anticipated future gain. For a long time, it was thought to be a uniquely human trait. Children begin showing such abilities when they are about 4. But it turned out that chimpanzees, bonobos and orangutans have this ability too, making tools to use later on.


In 2007, researchers at the University of Cambridge showed that scrub jays can cache food in places where they anticipate being hungry the next morning.

While the behaviour is flexible and requires planning, some argued that it might be an adaptation specific to caching food, which scrub jays and other members of the crow family do habitually, says Mathias Osvath of Lund University, Sweden.

Bartering birds

Osvath and his colleagues wanted to see if ravens could plan for the future in tasks that aren’t their natural behaviours, such as tool use and bartering with humans.

In one experiment, the ravens were first trained to use a stone to dislodge some dry dog food from a box. Later, the birds were shown a collection of objects, including the tool, without the box in sight. The researchers let the ravens select an object and 15 minutes later showed them the box at a different location with the reward in it. The birds had to drop the stone into the box to collect the food. The ravens succeeded, on average, in 11 of the 14 trials.

The birds also took part in a bartering test. Again, they were first trained, in this case to exchange a token for a reward. Later, they had to select the correct token from a batch of objects, hold on to it for 15 minutes, and then exchange it with an experimenter to get a reward. The birds picked the correct token 143 out of 144 times, and were able to exchange about 77 per cent of the tokens for the reward.

Ravens match great apes at planning Mathias Osvath/Lund University

The researchers then increased the delay between the tool or token selection and its use to 17 hours. The ravens succeeded in the task nearly 90 per cent of the time.

Crucially, the ravens were planning from the first trial onwards, suggesting that their success wasn’t due to habituation, says Osvath. “They can perform at the same levels as great apes, making a decision in the immediate situation for a future that will occur at another place,” he says.

“This is new, very exciting evidence which we didn’t have before,” says Markus Boeckle at the University of Cambridge. “[It’s evidence] that general intelligence has also developed in birds. This is very important for understanding how intelligence evolves.”

Journal reference: Science, DOI: 10.1126/science.aam8138