In a choice-test paradigm that has previously been used with rats and primates, researchers offered Octopus bimaculoides specimens a choice between a dark, enclosed shelter and an open arena containing live shore crabs — a preferred food. Across 42 trials with 14 individual animals, the octopuses spent roughly three-quarters of their available time in the shelter, emerging only briefly to feed before retreating again.
The result challenges the simpler model that cephalopods optimise primarily for energy gain. The authors interpret the strong shelter preference as evidence that octopuses experience something analogous to stress relief from enclosed spaces — a finding that adds to a growing body of work treating cephalopods as candidates for welfare-relevant cognitive states.
The work has direct implications for cephalopod aquaculture standards, which the European Union began tightening in 2024 after octopus farms were placed under sentience-based welfare review. The authors recommend that any captive housing for the species default to providing multiple enclosed shelter sites, even when food is freely available.