For the first clock time , a species of fish has demonstrated grounds of possible self - cognizance by pass the famous mirror exam .
In a serial of experimental observations conduct by Japanese researchers , bluestreak cleaner wrasse – a lilliputian coral reef fish – were able to recognize that their reflection represented their own trunk .
Until now , the only non - human animals that havepassed the trial – regarded among behaviorists as the bench mark for high level cognitive capacity – have been a handful of mammals ( several apes , elephants , orcas , and dolphins ) and hiss in the crow family . ( Acontroversial studysuggests that ants may have pass too )
However , several recentstudies have " reveal[ed ] that the perceptual and cognitive abilities of Pisces often agree or exceed those of other vertebrates , and suggest the opening that the cognitive skill of Pisces could more close near those found in humanity and apes , " the generator wrote in the pre - publication interlingual rendition of their report , currently posted onbioRxiv .
During a mirror exam experimentation , the animate being in question is place in front of a mirror after a colored mark , typically a toughie , is placed on a prominent part of its body . If the animal then tries to try and/or remove the mark from that part of itself , but does not set about to do so in the absence of a mirror or in reply to an invisible mark , the creature is considered to understand the nature of reflections , and is thus capable of understanding a construct of ego .
Though cleaner wrasse – selected by the squad due to retiring evidence of complex noesis – do not have script or beaks with which to investigate and seek to remove a mark with , they do show a specific behavior wherein they scratch constituent of their trunk against rock and other materials in monastic order remove irritants and parasite from their scales . This was used as the notch / fail cue for 10 cleaner wrasse field , all housed in separate tanks .
In a preliminary experiment , the research worker first keep the fauna ’ behavior in front of a mirror before adding marks into the mix . Seven of the wrasse glide by through all three stage of a behavior pattern that past research has identified in ego - recognizing animals . First , the Pisces the Fishes reacted to their manifestation as if it was another mortal , next they do strange behaviors not typically control without the mirror , and third , the Pisces the Fishes lead off to gaze at and closely try their reflection .
Moving on to the genuine mirror test , the squad injected a colored gel decent under the surface of the peel of eight of the wrasses , make a gull resembling an outside leech . Three of four wrasse marked on their throats showed repeated scrape in that area yet exhibited no reception to a non - marking injection and did not scrape when the mirror was scatty .
Three of four marked on the head engaged in important header scraping when the mirror was present , but the author did not base their decision off these somebody as they were examine heading scraping at other times too .
“ The results we demo here will by their nature lead to disputation and dispute , and we welcome this discussion , ” the authors wrote . “ We do not consider that the successful behavioural reply to all phases of the patsy trial should be take up as grounds of self - cognizance in the cleaner wrasse , but rather that these Pisces come to understand that the mirror expression typify their own body . ”
They conclude by noting that their findings could conduct to two distinct paradigm shifts in the field : Either we originate to entertain the possibility that fish , previously believed to be unintelligent animals , are self - mindful because they pass off the same test as ‘ higher ’ brute , or we resolve that these behaviors are base on a cognitive process other than ego - recognition .
“ If the former , what does this stand for for our understanding of animal intelligence information ? If the latter , what does this mean for our app and interpretation of the Saint Mark test as a system of measurement for animal cognitive ability ? ”
