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Can manta rays recognise themselves in a mirror?




Are manta rays self-aware? A recent study reveals that the manta ray may be the first fish to recognise themselves in a mirror.

New Scientist (March 21, 2016) published a Journal of Ethnology study from the University of South Florida in Tampa, America, on two giant manta rays.

Manta rays have the largest brains of any fish. They are not in the category of bony fish – instead they are cartilaginous fish (like sharks, skates, and sawfish). Their skeletons are made of cartilage, and not bone. Hence they are called chondrichthyes (Greek for cartilage fish).

Csilla Ari of the University of South Florida filmed two giant manta rays in a tank, with and without a mirror inside. The rays changed their behaviour in a way that suggests that they recognised themselves in the mirror – i.e. they recognised the reflections as themselves (as opposed to another manta ray).

They did not interact with the reflection, which is what you would expect if they thought it was another ray. Instead, they repeatedly moved their fins and circled in front of the mirror. This suggests that they could see whether their reflection moved when they moved. The frequency of their ‘repeated movements’ was much higher when the mirror was in the tank than when it was not.

The rays also blew bubbles in front of the mirror, which is behaviour that the researcher had not observed before. Csila Ari said, ‘The behavioural responses strongly imply the ability for self-awareness, especially considering that similar, or analogous, behavioural responses are considered proof of self-awareness in great apes.’

Only a few animals, mostly apes (gorilla, orangutan, and chimpanzees), pass the mirror test, which is widely used as a test for self-awareness. The test itself has been questioned by some scientists who do not think it is the best evidence of self-awareness.

The person who originally developed the mirror test, Gordon G. Gallup Jr of the University at Albany, New York, is also sceptical. Gallop said other studies showed that dolphins, elephants, monkeys, magpies, and even a robot, could recognise themselves in a mirror, but these studies were conducted with just one or two animals, and the results were not reproducible or conclusive. Again, this study had only two manta rays.

Journal of Ethology, DOI: 10.1007/s10164-016-0462-z

https://www.newscientist.com/article/2081640-manta-rays-are-first-fish-to-recognise-themselves-in-a-mirror/



MARTINA NICOLLS is the author of:- The Shortness of Life: A Mongolian Lament (2015), Liberia’s Deadest Ends (2012), Bardot’s Comet (2011), Kashmir on a Knife-Edge (2010) and The Sudan Curse (2009).
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