A new study has shown that crows can count out loud, making them the first known species besides humans capable of producing voluntary vocalizations to represent an understanding of quantity.
This does not imply that the birds have an abstract understanding of numbers like adults do, but rather that they're capable of doing what's known as proto-counting, just like toddlers.
Highlights
- Crows are the first known species besides humans that can count out loud, according to a new study.
- The birds can "proto-count" like toddlers, understanding quantities without an abstract comprehension of numbers.
- After a year of training, crows were able to respond to a number on a screen or an auditory cue with a matching number of calls.
When learning to count, toddlers first produce the number of sounds associated with quantity. They may get it wrong by saying "one, two, four" or "dog, dog, dog," but they understand that there are three dogs, even if they still can't grasp the abstract meaning of "three." Carrion crows have surprisingly shown the same ability.
Image credits: Pexels Umar Andrabi
Diana Liao, a neurobiologist and post-doctoral researcher at the University of Tubingen in Germany, who led the study, trained three carrion crows over a span of a year to associate colored numerals (1, 2, 3, and 4) and neutral auditory cues (sounds that weren't linked to any natural threat) with a corresponding series of vocalizations.
The researchers presented each crow with a number on a screen or a pre-recorded sound and rewarded the bird with food if and when they produced a matching number of calls.
After a year, the crows were able to produce the number of calls that lined up with the number they saw on screen or with the audio cues they heard. The animals marked the end of their responses by pecking an "enter key" on the screen.
Crows are the first known species besides humans capable of producing voluntary vocalizations to represent an understanding of quantity
Image credits: Pexels/ Mike Bird
Across twenty sessions each, all three crows demonstrated their capacity to match their vocalizations with the cues at a much higher rate than chance, as per Popular Science.
The crows displayed 100% accuracy in their responses for the number one, over 60% for the number two, more than 50% for three, and roughly 40% for the number four.
"Producing a specific number of vocalizations with purpose requires a sophisticated combination of numerical abilities and vocal control," wrote the team of researchers, who published their study on May 23 in the journal Science.
This does not mean that the animals have an abstract understanding of numbers like adults do, but rather that they're capable of "proto-counting," just like toddlers
Image credits: Pexels/Pixabay
"Our results demonstrate that crows can flexibly and deliberately produce an instructed number of vocalizations by using the 'approximate number system,' a non-symbolic number estimation system shared by humans and animals," they added.
Furthermore, scientists found that the timing and sound of the crows' first calls were linked to how many vocalizations were made subsequently, which would suggest that they planned their responses from the very first caw, as per ScienceAlert.
"The acoustic features of vocal units predicted their order in the sequence and could be used to read out counting errors during vocal production," the study reads.
"This competency in crows mirrors toddlers' enumeration skills before they learn to understand cardinal number words," the study reads
Image credits: Pexels/Pixabay
Researchers presented each crow with a number on a screen and rewarded the bird with food if and when they produced a matching number of calls
Image credits: Liao et al
It adds: "This competency in crows also mirrors toddlers' enumeration skills before they learn to understand cardinal number words and may therefore constitute an evolutionary precursor of true counting where numbers are part of a combinatorial symbol system."
Other species have previously demonstrated some level of quantitative reasoning—a 2014 study revealed macaques can do basic arithmetic—but this is the first instance of an animal communicating an understanding of quantity using vocalizations.
"I think all birds are capable of more than humans know," someone wrote
