Researchers at Dartmouth report that octopuses can learn to use mirrors as a tool to locate hidden food, a behavior previously documented only in some vertebrates. In a study published in Current Biology, three California two-spot octopuses (Octopus bimaculoides) trained in Dartmouth’s Octopus Lab correctly identified the location of a concealed reward about 73% of the time, indicating they were inferring where the prey was rather than simply reacting to a reflection.
The team first familiarized the animals with a mirror and then trained them to link reflections with real-world locations. During training, a live crab was placed inside a glass jar so the octopus could see it only via the mirror; to reach the crab the animal had to turn 90 degrees and move around a corner. For formal testing, researchers used a virtual crab image to avoid scent-based cues, placing each octopus in a start box with a mirror directly in front. The virtual crab appeared behind the animal, either to its left or right, visible only through the mirror. To earn a live crab reward, the octopus had to recognise where the image was actually located and move to that side instead of attacking the mirror itself.
Lead author Mary Kieseler, who carried out the work at Dartmouth and is now a postdoctoral researcher at the University of Fribourg, said: “Our findings are the first to demonstrate that invertebrates can use mirrors to understand their environment to find prey. It’s a skill that previously has only been documented in vertebrates, such as in some mammals and some birds.” Senior author Peter Tse, a cognitive neuroscientist at Dartmouth, emphasised the learned nature of the ability: “We don’t enter the world knowing how to use a mirror but learn how to use a mirror,” he said, adding that “Octopuses can also learn how to use a mirror to infer where things are in the world.”
Overhead tracking focused on a point between each octopus’s eyes on the mantle and recorded the routes taken to the reward. Although the animals did not always choose the shortest path, they became faster at reaching the correct location as trials progressed; some even climbed over the side of the box to reach the projected image’s location rather than swimming around it.
The researchers argue the result sheds light on the evolution of intelligence. Kieseler noted that octopuses are evolutionarily distant from humans-our last common ancestor was a worm 350 to 500 million years ago-so the ability to use mirrors suggests convergent evolution of spatial-cognition mechanisms. Tse added that the finding supports the idea that octopuses may form internal maps of their complex reef and seafloor habitats: “Hunters are very effective when they have a mental map of their territory… Our work suggests that octopuses might also have internal maps, an internal representation of space.”
Original Source: https://theshillongtimes.com/2026/06/07/octopuses-can-use-mirrors-to-locate-food-says-study/
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Publish Date: 2026-06-07 03:33:00
