Now, new tests seem to show that ravens can even plan for future events and delay their own gratification — something scientists initially thought only chimpanzees and humans could do.
Researchers in Sweden trained ravens to use a tool to open a box for a treat or to barter tokens for food. The birds would even keep their tools and tokens overnight if they knew they could trade them for a treat in the morning.
And when researchers gave the ravens a choice between an immediate reward and waiting to trade their token or box-opening tool for a bigger payoff later, they found the birds were usually willing to wait.
These new tests suggest ravens have self-control on par with some great apes — and they're even potentially smarter than some of them when it comes to bartering tokens for food.
What's more, the researchers think corvids evolved their forward-thinking abilities all on their own: They haven't shared a common ancestor with great apes for more than 300 million years.