Ravens and crows defy the phrase "birdbrained" altogether. These clever birds are known for assembling their own tools, possessing a form of consciousness and thinking about the future, earning them a top spot among Earth's most intelligent animals alongside dolphins, great apes and elephants.
They consistently surprise scientists with their wits, and now a new study published last week in Scientific Reports suggests that four-month-old ravens score similarly to adult chimpanzees and orangutans when put through a series of social and physical tests, reports Sara Rigby for Science Focus.
To come to this conclusion, a team of scientists hand-raised eight ravens and tested their cognitive abilities every four months since they hatched. The tasks were focused on testing how the birds interact with each other and with the physical world around them. Specifically, the researchers were interested in testing the birds' spatial memory, basic math skills, communication skills, and object permanence, which is the ability to recognize that an object exists even when it's hidden, reports Chrissy Sexton for Earth.com.
For example, in one of the tests, the ravens were shown a treat that was then hidden under a cup. Like a shell game on a beach boardwalk, when the researcher moved the cup around, the bird was still able to identify where the food was, reports Rachel Nuwer for Scientific American.
"We now have very strong evidence to say that, at least in the tasks we used, ravens are very similar to great apes," lead author Simone Pika, a cognitive scientist at Osnabrück University in Germany, tells Scientific American. "Across a whole spectrum of cognitive skills, their intelligence is really quite amazing."
The birds were put through 33 tests and passed with flying colors at just four months old. When their results were compared with those of fully grown chimpanzees and orangutans, the team found that the young ravens scored similarly to the great apes, surprising the scientists, reports Scientific American.
"Great apes and primates in general have, for quite a long time now, been praised for their 'extraordinary' cognitive abilities, but we now find that other taxa, including birds, show similar cognitive performance," Claudia Wascher, a behavioral ecologist at Anglia Ruskin University in England who was not involved in this study, tells Scientific American.
In another surprising twist, the team found that there wasn't a significant difference in the scores of four-month-old ravens and the 16-month-old birds. This find suggests that their brains are nearly or fully developed at around the four-month mark, reports Mike McRae for ScienceAlert.
"This may be due to the fact, that at four months of age, young ravens are already quite independent," Pika tells Science Focus. "Hence, they need to be cognitively on top of things to deal with these new challenges."
But this study comes with caveats, reports Scientific American. The team had a sample size of only eight ravens. Plus, their behaviors may not reflect the species as a whole since they were raised in captivity and accustomed to interacting with humans.
Regardless, ravens continue to astonish people with their remarkable physical and social skills, adding fuel to a friendly argument among ornithologists and mammologists over who's smarter: birds or mammals?