Mirror, mirror, on the … surface? Mirror-guided learning in octopuses.

Kieseler et al. (2026) show that Octopus bimaculoides can learn to use a mirror reflection to navigate to an out-of-view target for a reward, providing the first demonstration of mirror-mediated foraging, and of potential spatial reflection use, in an invertebrate. We situate this within a framework that distinguishes between different types of mirror information processing (including mirror self-recognition), examine statistical and stimulus-related caveats, and argue that reflection use may be more ecologically grounded in cephalopods than an aquatic lifestyle might suggest.