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: girl cools off in a water fountain
Europe sweats through new heatwave, with worse to comeNews

Europe sweats through new heatwave, with worse to come

Paris, France | AFP | Muser NewsDesk France banned alcohol in red-alert areas Sunday, Spain and Germany cancelled or postponed sports events and Britain warned of…
SourceSourceJune 22, 2026 Full article
Landscape of building ruins and bare trees in the water under a cloudy sky on a gloomy day - Climate Change
Europe facing urgent climate risks: EEA report warns of ‘catastrophic’ consequencesNewsClimate

Europe facing urgent climate risks: EEA report warns of ‘catastrophic’ consequences

Europe is rapidly becoming the epicenter of climate change, with unprecedented warming trends threatening the continent's very foundation. The European Environment Agency (EEA) has sounded…
Adrian AlexandreAdrian AlexandreMarch 12, 2024 Full article
Image: Two hands are holding a small earth globe
Bridging the early warning gap: WMO marks 75 years of advancing global resilienceNews

Bridging the early warning gap: WMO marks 75 years of advancing global resilience

A changing climate, a growing need for warnings The role of meteorological services in global security Early warnings for all: progress and challenges Expanding global…
Muser NewsDeskMuser NewsDeskMarch 23, 2025 Full article