Mirror, mirror, in my tank, who’s the biggest fish of all?
Imagine if the reflection in the mirror wasn’t of a person but of a fish. Would it still recognize itself and make decisions based on what it saw?
A research group at Osaka Metropolitan University has discovered that Bluestreak cleaner wrasse (Labroides dimidiatus) possesses mental states like body image, standards, intentions, and goals, making them the first non-human animals to demonstrate elements of private self-awareness.
This was evident as they checked their own body size in a mirror before deciding whether to attack other fish slightly larger or smaller than themselves – a remarkable display of self-awareness in the animal kingdom.
The research team from OMU Graduate School of Science, including student Taiga Kobayashi, Specially Appointed Professor Masanori Kohda, Professor Satoshi Awata, and Specially Appointed Researcher Shumpei Sogawa, along with Professor Redouan Bshary of the University of Neuchâtel in Switzerland, made a groundbreaking discovery last year. They found that cleaner wrasse could recognize photographs of themselves by identifying their own face in mirror self-recognition tests.
This latest research reveals that the cleaner wrasse uses mirrors to check their own body size against that of other fish, and even predict the outcome of potential fights. This behavior demonstrates a sophisticated level of self-awareness and cognitive ability in these fascinating fish.
“The results that fish can use the mirror as a tool can help clarify the similarities between human and non-human animal self-awareness and provide important clues to elucidate how self-awareness has evolved,” doctoral candidate Kobayashi declared.
Journal reference:
- Taiga Kobayashi, Masanori Kohda, Satoshi Awata, Redouan Bshary & Shumpei Sogawa. Cleaner fish with mirror self-recognition capacity precisely realize their body size based on their mental image. Scientific Reports, 2024; DOI: 10.1038/s41598-024-70138-7