Octopus arms are probably the most complex and flexible structures in nature

The octopus is a creature that continues to surprise scientists and inspire engineers. With eight arms that move in ways no human limb can, it demonstrates flexibility and control that seem almost otherworldly.

Each arm bends, twists, elongates, and shortens with unmatched precision, enabling these animals to hunt, hide, and explore with ease.

Researchers hope that unlocking the secrets of these movements may guide the design of flexible robotic arms capable of lifesaving missions.

Imagine a robotic arm slipping through rubble after a building collapse, delivering food or medicine to someone trapped below.

This vision has motivated scientists to study octopus arms in detail – both in the laboratory and in their natural environment.

Until recently, most studies were limited to tanks, where behaviors may not reflect the complexity of life in the wild. That gap is now being addressed.

Understanding octopus intelligence

Octopuses are some of the most intelligent invertebrates on Earth. Unlike most animals without backbones, they can solve puzzles, open jars, and even escape from aquariums by remembering routes back to the ocean.

Their brains are incredibly complex, with about 500 million neurons – similar to a dog. What makes them even more fascinating is that two-thirds of those neurons are in their arms.

This means each arm can sense, move, and even make decisions on its own while still communicating with the central brain. It’s like having eight mini-brains working together with one big brain.

Their intelligence also shows up in how they hunt and survive. Octopuses use tools, like carrying coconut shells to hide inside when threatened, and they can change color and texture in an instant to camouflage perfectly against rocks or coral.

They’ve been observed watching other animals and learning from them, which is rare in the animal kingdom.

Flexible octopus arms inspire robotics

A new study from the Marine Biological Laboratory in Woods Hole and Florida Atlantic University has provided the most comprehensive analysis of octopus arm movements in natural habitats.

Researchers recorded 25 wild octopuses in six locations, ranging from the Caribbean to Spain. The footage captured thousands of arm movements across a variety of behaviors, including foraging, locomotion, and even defense.

“I’ve been trying for a long time to work out the natural behavior of cephalopods in their natural habitat,” said MBL Senior Scientist Roger Hanlon, who led the project.

“Studying and recording octopus behavior from wild octopuses in the field gave us the opportunity to analyze a larger behavioral repertoire and further understand how they use their arms to achieve such complex behaviors,” added Chelsea Bennice, research fellow at FAU.

Guided by touch, not sight

Octopuses rely heavily on touch, guided by sensory organs in their arm suckers. “The octopus is a very tactile animal – it’s more tactile than visual,” said Hanlon.

Each of their nearly 100 suckers per arm contains chemosensory-tactile receptors, combining functions similar to the human nose, lips, and tongue.

Finding octopuses to observe was not simple. Their camouflage skills make them almost invisible in coral reefs or sandy seabeds. Divers often relied on clues like discarded shells and food debris near their dens.

Once located, octopuses emerged briefly from hiding, offering precious opportunities to record their natural actions.

These moments revealed unique hunting strategies, arm movements, and subtle interactions with their environment otherwise impossible to witness.

Complex arm mechanics of octopuses

The researchers identified 12 distinct arm actions across 15 behaviors, built from four fundamental deformations: shortening, elongating, bending, and torsion. They discovered a pattern of specialization within each arm.

For instance, elongation and shortening were most common near the base, while bending occurred more at the tips.

This functional partitioning allows octopuses to combine motions across arms for tasks like crawling, probing reef crevices, or launching sudden prey attacks.

“These are the actions that make up the whole complex of octopus behaviors,” said study co-author Kendra Buresch.

In the wild, researchers observed octopuses using different combinations of arm actions – sometimes relying on a single arm for tasks like grabbing food, and other times coordinating multiple arms for behaviors such as crawling or launching a parachute attack.

Behavior that guides technology

The findings go beyond understanding animal behavior. With nearly 7,000 observed arm deformations, the study highlights an extraordinary degree of control and flexibility.

This knowledge may inform robotics research, where engineers seek to design soft, adaptable arms capable of both precise and exploratory tasks.

“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 said.

Lessons in flexibility and change

From the ocean floor to robotics labs, octopuses continue to inspire, offering lessons in both biology and technology.

Their flexible arms not only influence the design of machines that could navigate disaster zones or deep-sea environments, but also remind us how problem-solving in nature often leads to solutions with real-world applications.

Beyond robotics, their adaptability symbolizes the broader principle that survival depends on innovation and change, a message equally relevant to ecosystems, human health, and future technologies.

The study is published in the journal Scientific Reports.

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