ABOVE: Cleaner wrasses groom a porcupine pufferfish
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We humans look in the mirror and take in our reflections. We adjust our clothes and wipe crumbs off our faces because we realize that the person staring back at us is our own self. Since the 1970s, researchers have been using mirrors to probe the minds of animals, gleaning clues from how they interact with and investigate their reflections in a quest to understand their cognition.
A study published in PLOS Biology this month (February 7) suggests that fish may join the ranks of animals that recognize themselves in a mirror. The researchers documented the behavior of the cleaner wrasse (Labroides dimidiatus), a coral reef species famous for its symbiotic grooming—it eats parasites residing on other fish—in front of its reflection. The authors concluded that the fish possessed mirror self-recognition by passing what’s called the mark test. It’s a bold claim ...
