A new study suggests that roosters may be able to recognize themselves in mirrors, which is considered a key test of self-awareness in animals. This finding challenges the idea that self-recognition is limited to a few animal species.
The traditional mirror self-recognition test involves placing a mark on an animal’s body that can only be seen in a mirror. If the animal interacts with the mark while looking at its reflection, it suggests that it understands the reflection represents its own body. Some species that have passed this test include great apes, dolphins, elephants, and magpies. Recently, there have been claims that other species, such as penguins, horses, cleaner wrasse fish, and manta rays, have also passed the test, but these claims remain controversial.
The variability of results from the mirror self-recognition test led researchers to question whether the lack of motivation to investigate the marks is the reason why many animals fail the test. To explore this, Sonja Hillemacher and her colleagues from the University of Bonn in Germany decided to study roosters, which are known to loudly alert other chickens to nearby predators but remain quiet when alone.
In the study, 68 roosters were individually tested in an arena divided by a wire mesh. One side of the arena had a rooster, while the other side was either empty or had another rooster behind a mirror. The researchers also projected the silhouette of a hawk on the ceiling to mimic a threat. They found that when a rooster was with another rooster, it raised the alarm more frequently compared to when it was alone, regardless of whether it could see its own reflection. This suggests that roosters can distinguish between reflection and reality through vision.
Based on the similar behavior displayed by the roosters when alone and with a reflection, the researchers propose that the birds may recognize their own reflection. This discovery challenges the idea that self-recognition is exclusive to certain species.
Some experts believe that the traditional mark test, which relies on animals interacting with marks, may not be suitable for testing self-recognition in non-ape species. Nathan Emery, from Queen Mary University of London, suggests that researchers should explore alternative methods to reveal animals’ existing self-recognition skills.
While the study shows promising results, both Emery and Hillemacher caution against concluding that chickens definitively recognize themselves in mirrors. They suggest that the unusual behavior of a reflection, such as mimicking every movement, could provoke a different response than encountering another rooster.
