10 Animal Behaviors Scientists Have Only Recently Begun to Understand
8. Fish Cooperation and Mutualistic Relationships
The discovery of sophisticated cooperative behaviors among fish species has revolutionized our understanding of cognitive abilities in aquatic vertebrates and revealed complex social strategies that were previously thought to require higher-order thinking. Cleaner fish, particularly the cleaner wrasse Labroides dimidiatus, engage in mutualistic relationships with client fish that demonstrate remarkable social cognition, including the ability to recognize individual clients, remember their preferences, and adjust their behavior based on the social context of each interaction. Dr. Redouan Bshary's groundbreaking research has shown that cleaner fish can engage in tactical deception, providing better service to new clients when regular clients are watching, and can even use punishment and reconciliation strategies to maintain long-term cooperative relationships. These fish demonstrate an understanding of reputation and the importance of maintaining their standing in the community, as clients will seek out cleaners with good reputations and avoid those known for cheating. Perhaps most remarkably, cleaner fish have been shown to pass the mirror self-recognition test, joining the exclusive group of animals with demonstrated self-awareness, and can learn to use tools and solve complex problems that require planning and foresight. Grouper fish engage in interspecies cooperation with moray eels, using specific head-shaking signals to recruit eels as hunting partners, with each species contributing unique abilities to increase hunting success for both parties. The neurological mechanisms underlying these cooperative behaviors appear to involve advanced social cognition networks in fish brains that were previously thought to be too simple to support such complex behaviors, challenging our assumptions about the relationship between brain size and cognitive sophistication and revealing that intelligence can evolve in diverse forms across different environmental contexts.
