Octopuses Learn to Use Mirrors to Find Hidden Food

Imagine being smart enough to figure out how mirrors work without anyone teaching you. That's exactly what three California two-spot octopuses just proved they could do at Dartmouth's Octopus Lab.

Researchers trained the octopuses to use mirrors to find food they couldn't see directly. The animals had to look at a reflection, understand where the real food was located behind them, and then turn around to grab it. They succeeded about 73% of the time.

"It's a skill that previously has only been documented in vertebrates, such as in some mammals and some birds," says lead researcher Mary Kieseler. No invertebrate had ever demonstrated this ability before.

The experiment was surprisingly clever. Scientists placed each octopus in a box with a mirror in front of it. Then they projected an image of a crab behind the octopus, visible only in the reflection. If the animal understood what the mirror showed, it would turn around and move toward the correct side to earn a real crab reward.

The octopuses didn't just get it right most of the time. They also got faster with practice, climbing over the box walls and finding shortcuts to reach their prizes.

This matters because octopuses are incredibly distant relatives of ours. Our last common ancestor was a worm that lived 350 to 500 million years ago. Yet somehow, these ocean dwellers evolved similar problem-solving skills completely independently.

Why This Inspires

The discovery suggests that intelligence might evolve in similar ways across vastly different species facing similar challenges. Octopuses hunt by sneaking up and pouncing on prey in complex environments like coral reefs, just like cats do on land.

Scientists believe this hunting strategy benefits from mental maps of the surrounding area. The mirror test hints that octopuses might create internal representations of space, helping them navigate and hunt more effectively.

The findings add another remarkable talent to octopuses' already impressive resume, which includes opening jars, solving puzzles, and famously escaping aquariums. These animals continue to surprise us with abilities we once thought were uniquely ours.