Tiny Cleaner Wrasse Sparks Big Questions About Self-Awareness
A cleaner wrasse fish passed a revised mirror-self-recognition test, suggesting self-awareness may be more widespread in vertebrates. In the study, researchers marked the fish before introducing a mirror, and the fish began scraping off the perceived parasite after seeing its reflection—on average about 82 minutes later—while also engaging in behavior like carrying a shrimp to the mirror to probe how the reflection works. This contingency testing and self-directed tool use extend previous work from 2018, implying that self-awareness could have evolved in bony fishes and may have implications for evolution, animal welfare, and AI research; the findings are reported in Scientific Reports.
