Researchers from Florida Atlantic University’s Charles E. Schmidt College of Science, in collaboration with the Marine Biological Laboratory in Woods Hole, Massachusetts, have published a study detailing how wild octopuses use their arms across different natural habitats. The research, released in Scientific Reports, is described as the first to connect arm movements to overall animal behaviors in complex underwater environments.
The team analyzed nearly 4,000 arm movements captured from 25 video recordings of three wild octopus species found in six shallow-water habitats—five in the Caribbean and one in Spain. They identified 12 distinct arm actions related to 15 different behaviors. These actions involved four basic types of arm deformation: shortening, elongating, bending, and torsion.
“Observing them in the wild, we saw octopuses use different combinations of arm actions – sometimes just one arm for tasks like grabbing food, and other times multiple arms working together for behaviors like crawling or launching a parachute attack – a hunting technique they use to catch prey,” said Chelsea O. Bennice, Ph.D., lead author and research fellow at FAU’s Marine Laboratory.
The study found that while each arm can perform all action types, there is a pattern where front arms are mainly used for exploration and back arms primarily support movement. Octopuses also showed flexibility by using single arms for multiple movements at once and coordinating different actions across several arms.
“When octopuses move across an open environment, they skillfully use multiple arms to stay camouflaged from predators, such as the moving rock trick or looking like floating seaweed,” Bennice said. “Beyond foraging and locomotion, their arm strength and flexibility are essential for building dens, fending off predators, and competing with rival males during mating. These versatile abilities allow octopuses to thrive in a wide range of habitats.”
Analysis of almost 7,000 observed deformations revealed that all four types—bend, elongate, shorten and torsion—occurred in every arm. However, certain regions of each arm specialized: bends were mostly near the tips while elongations occurred closer to the body.
“I’m a strong believer that you have to get into the natural world, and especially the sensory world, of whatever animal you study,” said Roger Hanlon, Ph.D., co-author and senior scientist at the Marine Biological Laboratory. “The fieldwork is very arduous, and it takes a lot of luck to get valid natural behaviors.”
The six studied habitats ranged from smooth sandy seafloors to complex coral reefs.
“Understanding these natural behaviors not only deepens our knowledge of octopus biology but also opens exciting new avenues in fields like neuroscience, animal behavior and even soft robotics inspired by these remarkable creatures,” Bennice added.
Other contributors include Kendra C. Buresch (marine biologist), Jennifer H. Grossman (undergraduate student), and Tyla D. Morano—all affiliated with the Marine Biological Laboratory.
Funding came from the Sholley Foundation, Ben-Veniste Family Foundation, and United States Office of Naval Research.
