How octopuses squeeze through tiny openings, step by step.
Researchers including Michael Kuba and Wenci Xin report that common octopuses follow a consistent step-by-step sequence to squeeze through holes, with an added fourth step when the opening is narrower.
Octopuses are known for escaping tanks and boats through narrow gaps, and researchers have now described how some of them do it. They report in the Journal of Experimental Biology on November 5 that the escapes follow a consistent, step-by-step plan.
Michael Kuba, a biologist at the University of Naples Federico II in Italy, and colleagues observed three common octopuses (Octopus vulgaris) and four Mayan octopuses (Octopus maya). For each animal, the team measured the distance between the eyes as a stand-in for the size of the rigid cartilage around the brain. They then built acrylic boxes with holes slightly smaller or larger than that measurement and placed the octopuses inside.
When a hole was wider than the distance between their eyes, common octopuses escaped in three steps. They pushed one or two arms through, threaded a couple more through, and then used those arms to push against the box and pull the head and remaining arms out in one motion. The whole process took a few seconds. With a narrower hole, they added a fourth step: all arms went through first, followed by the head and mantle.
Mayan octopuses were more cautious. Faced with the narrower hole, they usually ignored it rather than trying to fit through. Kuba said the difference could come from their biology or their environment, since Mayan octopuses live in sandy, rocky areas where they may hide under rocks but rarely need to cram through holes.
The team hopes the findings can inform soft robots that change shape to enter hard-to-reach spaces. "This incredible capability could enable robots to overcome environmental limitations and enter spaces that are difficult to reach," said Wenci Xin, a robotics researcher at the National University of Singapore.
Robyn Crook, an evolutionary biologist at San Francisco State University who was not involved in the work, noted that octopuses may use different tactics for slits or tubes than for round holes. She said the strategies had not been examined systematically before. Robots built for tiny holes are currently mostly snake-shaped.
At a Glance
- The study appeared in the Journal of Experimental Biology on November 5, 2026.
- Researchers tested three common octopuses and four Mayan octopuses using acrylic boxes with holes sized relative to eye spacing.
- Common octopuses escaped in three steps through wider holes and used a fourth step for narrower ones.
- Mayan octopuses usually ignored the narrower hole instead of trying to pass through it.
Sources
This brief was written by Brightside Report from the reporting linked above. Spot an error? Request a correction.