It’s no secret that corvids are capable of some amazing feats of creative and intelligent thinking, but this newfound ability has blown us away.
A team of scientists has shown that crows can ‘count’ out loud, producing a specific, deliberate number of crows in response to visual and auditory cues. While other animals such as honeybees have shown the ability to understand numbers, this specific manifestation of digital literacy has not yet been observed in any species other than humans.
“Producing a fixed number of vocalizations with a goal requires a sophisticated combination of numerical abilities and vocal control.” Writes the team of researchers Led by neuroscientist Diana Liao of the University of Tübingen in Germany.
“Whether this ability exists in animals other than humans is not yet known. We have shown that crows can flexibly produce variable numbers from one to four sounds in response to random cues associated with numerical values.”
The ability to count out loud is different from understanding numbers. It requires not only this understanding, but purposeful voice control in order to communicate. Humans are known to use speech to count numbers and communicate quantities, an ability learned at an early age.
When young children learn to count, learning specific numbers associated with specific quantities may take some time to master. Meanwhile, children can sometimes use random numbers to make a phonetic tally. Instead of counting “one, two, three,” they might say “one, one, four,” or “three, ten, one.” The number of pronunciations is correct, but the words themselves are mixed up.
The biological origin of token counting is unknown, but crows are known to understand Difficult numerical concepts such as zeroLiao and his colleagues thought they represented a good candidate for exploring more complex number skills.
They conducted their study on three carrion crows (Corvus Coron), which the researchers trained to produce a variable number of sounds, between one and four, when presented with a random symbol or audio signal. Once the required number of cows had been produced, the crows then had to peck the target to signal the task was over.
The researchers found that the three crows were able to produce the correct number of caws in response to the cues, with the occasional error often appearing as one caw too many or too few.
The researchers say this is similar to the way young children count, using an approximate, non-symbolic number system that is planned in advance before their first vocalization.
Interestingly, the timing and sound of the first vocalization in the sequence were related to the number of vocalizations made subsequently, and each vocalization in the sequence had acoustic features specific to its place in that sequence.
This is a particularly impressive feat for crows since making intentional sounds is more difficult and has longer reaction times than clicks or head movements, for example.
It could indicate a previously unknown channel of bird communication in the wild. For example, chickadees produce a greater number of ‘d’ sounds in their alert calls to larger predators.
“Our results show that crows can flexibly and deliberately produce a specific number of sounds using the ‘approximate number system,’ a non-symbolic number estimation system shared by humans and animals.” The researchers write in their paper.
“This competence in crows also reflects the enumeration skills of young children before they learn to understand basic number words, and thus may constitute a developmental precursor to true counting where numbers are part of the combinatorial symbol system.”
The research was published in Sciences.
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