fish

Yes, if you believe the mirror test proves it: The bluestreak cleaner wrasse has passed the famous mirror test for self-recognition (originally intended for primate apes and monkeys). According to a recent paper (open access), three out of four fish tested by researchers from Osaka City University in Japan were able to learn to identify the object in a mirror as their own images. But what does that mean? When chimpanzees, dolphins, elephants, and magpies passed the test1, researchers theorized that these animals, recognized as intelligent, were demonstrating a concept of “self.” Now they are not so sure. Is the cleaner wrasse, which grooms other fish for parasites, really self-aware? Are fish much smarter than we think? More. But what Read More ›