Prepare to be amazed and have your perceptions of animal intelligence turned upside down! A tiny fish, the cleaner wrasse, has just passed an intelligence test that was once considered a hallmark of great apes. But here's where it gets controversial...
Mirror tests, a common scientific method, are used to gauge self-recognition in animals, giving us a glimpse into their cognitive abilities. When you fix your smudged eyeliner by looking in the mirror, you're demonstrating self-recognition. You know that smudge is out of place, and the mirror helps you pinpoint exactly where to wipe it away. This simple act is a sign of intelligence that scientists have long used to assess other species.
Chimpanzees, elephants, and dolphins have all passed this mark test, leading many to believe they possess a level of intelligence similar to humans. But the cleaner wrasse, a tiny marine fish, has now joined this exclusive club. In 2018, it was reported that this fish not only recognized itself in the mirror but also used food to explore the mirror's properties.
The cleaner wrasse's modus operandi is to clean parasites and dead tissue from other fish, so it's no surprise that it would be drawn to a 'parasite-like' mark on its own body. However, the founder of the mirror mark test, Gordon Gallup, expressed skepticism, believing the fish mistook the mark for a parasite on another fish.
Enter a team of scientists from Osaka Metropolitan University in Japan and the University of Neuchâtel in Switzerland. They tweaked the experiment to further test the wrasse's self-awareness. Instead of habituating the fish to the mirror first, they marked the fish and then introduced the mirror. This allowed the fish to identify the 'parasite' on its own body before encountering its reflection, providing a more controlled environment.
The results were astonishing. The fish reacted quickly, trying to rub off the 'parasite' within an average of 82 minutes. This implies self-awareness even before being exposed to the mirror. But the real surprise came when the scientists noticed some fish performing an unusual behavior. They would pick up a piece of shrimp, carry it to the mirror, and drop it, following the reflection closely with their mouths.
The scientists believe this behavior is the fish's way of exploring the mirror's properties, using an external object to understand how reflected images work. This 'contingency testing' and mirror tool use has been observed in other species that failed the mark-based mirror test, such as pigs, rhesus monkeys, manta rays, and corvids.
Biologist Masanori Kohda, involved in both this new study and the original paper, believes these findings will not only influence academic issues like evolutionary theory and concepts of self but also directly impact animal welfare, medical research, and even AI studies.
The team's research suggests that self-awareness, once thought to be unique to great apes, is actually a skill that may have evolved in a much wider range of animals, including fish. Their results indicate that self-awareness could have emerged as early as 450 million years ago with the bony fishes and is likely widespread across vertebrates.
This research, published in Scientific Reports, challenges our understanding of animal intelligence and opens up a world of possibilities. So, what do you think? Are we underestimating the cognitive abilities of our aquatic friends? The floor is open for discussion!
