Study Reveals Octopus Strategies for Squeezing Through Tight Gaps, Offering Insights for Soft Robotics
Researchers observed how common octopuses navigate holes of varying sizes, identifying distinct movement sequences that could inform the design of flexible robots for confined environments.
Researchers from Italy, Austria and the National University of Singapore examined how common octopuses (Octopus vulgaris) pass through holes of different diameters. By recording the animals' movements, the team identified basic motor patterns, or "motor primitives," that the octopuses combine to negotiate narrow openings.
When the aperture was relatively large, the octopuses followed a three-step sequence: probing the opening with one arm, shifting additional arms into the gap, and then squeezing the mantle and remaining arms through in a single motion. For smaller openings, the final stage split into two steps, first shifting the remaining arms and then passing the mantle separately, resulting in a four-step strategy. The animals were able to use this method to pass through holes slightly smaller than the distance between their eyes, using the stiff cartilage sheath around their central nervous system as a size reference.
"With sophisticated behaviors, a flexible body and unique motor control, octopuses are compelling models for both biological and bio-inspired robotics," the authors wrote.
"Their lack of a rigid skeleton allows them to undergo extreme deformations, letting them navigate tight apertures and narrow geometries, offering a biological solution to one of the most persistent challenges in robotics," the paper added.
The findings suggest that the identified movement strategies could guide the development of soft robots for search-and-rescue missions, where current designs often rely on snake-like locomotion. An octopus-inspired approach may enable robots to incorporate more sensors and manipulators, enhancing adaptability in confined spaces.
"By identifying common strategies underlying this behavior, our study contributes a new potential combination of motor primitives and provides insights into the evolutionary intelligence that enables octopuses to adapt to environmental constraints," the researchers concluded.