We already know that crows are highly intelligent, with some scientists comparing their intelligence to that of a toddler. A recent study conducted by scientists at Germany’s University of Tübingen concluded that this comparison might be more accurate than anyone could assume.
According to a study published in Science, crows are capable of counting up to four. They use a “simplified” version of counting and rely on vocalization to perform it.
The scientists trained three European Carrion crows to caw a set number of times when presented with a particular audio recording or a display of numbers. Each time they were successful, the crows would receive a reward.
In the first experiment, the crows were supposed to caw once when they heard a guitar, caw twice when they heard a cash register sound, caw three times when presented with a recording of a drum roll, and finally, caw four times when they hear a frequency noise. In the second experiment, they were supposed to caw as many times as the number displayed on the screen indicated.
Once they were done “counting”, the crows were prompted to tap the screen in front of them.
The experiments showed that the crows made a noticeable pause before they started to count. They were correct every time they needed to count to one, and they were correct in counting to two 60% of the time. Counting up to three saw 50% correctness, and the birds were correct 40% of the time when they needed to count up to four.
According to John Marzluff, a wildlife biologist at the University of Washington, the pause before “counting” is arguably the most important discovery of the experiment.
“The longer reaction time suggests the birds had to think, organize, and encode the electrical signal from the brain to the muscles for calling. The delay is consistent with mental planning,” Marzluff, who wasn’t part of the study, told Science.