What if that proverbial man in the mirror was a… fish? Would it change its ways? According to an Osaka Metropolitan University-led research group, the answer is yes.

muser Kobayashi
A bluestreak cleaner wrasse (Labroides dimidiatus) swims in a tank at right, with its mirror image at left. Credit: Osaka Metropolitan University

In what researchers describe in Scientific Reports as the first demonstration of a non-human animal possessing certain mental states (e.g., mental body image, standards, intentions, goals), which are elements of private self-awareness, bluestreak cleaner wrasse (Labroides dimidiatus) checked their body size in a mirror before deciding whether to attack fish that were slightly larger or smaller than themselves.

The team – consisting of OMU Graduate School of Science student Taiga Kobayashi, Specially Appointed Professor Masanori Kohda, Professor Satoshi Awata, Specially Appointed Researcher Shumpei Sogawa, and Professor Redouan Bshary of Switzerland’s University of Neuchâtel – was also part of the group that last year reported the cleaner wrasse could recognize photographs of themselves, using their face through mirror self-recognition.

This time, the cleaner wrasse’s behavior of looking into a mirror installed in a tank when necessary suggested that the fish were using the mirror to check their own body size relative to other fish and predict the outcomes of potential fights.

“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.

***

This study was financially supported by JST SPRING (JPMJSP2139 to T.K.), JSPS KAKENHI (23KJ1829 to T.K., 19F19713 and 20K20630 to M.K., 22H02703 to S.A., and 20K20154 to S.S.), Swiss Science Foundation (310030_192673 to R.B.), and an OCU Strategic Research Grant 2018–2019 (to M.K. and S.A.).

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 14, 20202 (2024). DOI: 10.1038/s41598-024-70138-7

Article Source:
Press Release/Material by Osaka Metropolitan University
Featured image credit: François Libert | Flickr | CC BY-NC-SA

Image: Books with green board background
School’s out: how climate change threatens educationNews

School’s out: how climate change threatens education

Bangkok, Thailand | AFP Record-breaking heat last month that prompted governments in Asia to close schools offers fresh evidence of how climate change is threatening…
SourceSourceMay 9, 2024 Full article
Image: Herd of cows producing milk for Gruyere cheese in France in the spring
Denmark’s major parties agree on carbon tax on livestock: governmentNews

Denmark’s major parties agree on carbon tax on livestock: government

Copenhagen, Denmark | AFP - Denmark's government said Monday that the country's major parties had agreed on the details of the world's first carbon tax…
SourceSourceNovember 18, 2024 Full article
Satellite Image: Labanoras Regional Park, Lithuania
Image of the Day: Labanoras Regional Park’s freshwater tapestryNews

Image of the Day: Labanoras Regional Park’s freshwater tapestry

On March 22, 2025, World Water Day spotlights 'Glacier Preservation', emphasizing the critical role glaciers play in global water systems. While glaciers are vital, other…
Muser NewsDeskMuser NewsDeskMarch 22, 2025 Full article