New research reveals wild octopus arms in action
video:
The study is the first to relate arm movements in octopuses in the wild to whole animal behaviors in complex, real-world settings.
view moreCredit: Chelsea Bennice, Florida Atlantic University and Roger Hanlon, Woods Hole
Octopuses are among the most neurologically complex invertebrates, famed for their extraordinary dexterity. Their eight arms allow them to capture hidden prey, communicate, explore, and even mate across varied habitats.
Although octopus arms rank among some of the most flexible structures in nature, their full range of movement has rarely been studied in the wild – especially in a range of underwater habitats.
A new study by Florida Atlantic University’s Charles E. Schmidt College of Science, in collaboration with researchers from the Marine Biological Laboratory in Woods Hole, Massachusetts, provides a comprehensive look into how wild octopuses use their arms in natural habitats. By analyzing arm movements across diverse environments, this is the first study to relate arm movements to whole animal behaviors in complex, real-world settings.
The findings, published this week in Scientific Reports, reveal that every arm is capable of performing all action types; however, there was a clear pattern of arm partitioning: front arms mainly use movements to aid in exploration, while back arms use movements that primarily support movement.
Additionally, the octopuses demonstrated remarkable flexibility – single arms were shown to perform multiple arm movements simultaneously and different arm movements were coordinated across several arms, showcasing their complex motor control.
“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 a research fellow at FAU’s Marine Laboratory, Charles E. Schmidt College of Science.
Researchers quantified nearly 4,000 arm movements from 25 video recordings of three wild octopus species observed in six distinct shallow-water habitats – five located in the Caribbean and one in Spain. They identified 12 distinct arm actions across 15 behaviors, each involving one or more of four fundamental arm deformations: shortening (arm length decreases), elongating (arm length increases), bending (arm curves) and torsion (twisting).
“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,” said Bennice. “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.”
In the nearly 7,000 observed arm deformations, all four types – bend, elongate, shorten and torsion – were seen in every arm. However, different regions of each arm – proximal (closest to the body), medial (middle section) and distal (tip) – were found to specialize in specific types of arm deformation, reflecting a sophisticated level of functional specialization; bends mostly occurred near the tips, whereas elongations were more frequent 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, Marine Biological Laboratory in Woods Hole. “The fieldwork is very arduous, and it takes a lot of luck to get valid natural behaviors."
The six octopus habitats in this study varied from smooth, sandy seafloor to highly complex coral reef environments.
“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,” said Bennice.
Study co-authors are Kendra C. Buresch, a marine biologist; Jennifer H. Grossman; an undergraduate student, and Tyla D. Morano, all with the Marine Biological Laboratory in Woods Hole.
This research was supported in part by the Sholley Foundation, the Ben-Veniste Family Foundation, and the United States Office of Naval Research.
- FAU -
An octopus raises its arm in the wild.
An octopus Americanus in the wild.
A common octopus in South Florida waters.
Credit
Chelsea Bennice, Florida Atlantic University
Journal
Scientific Reports
Method of Research
Observational study
Subject of Research
Animals
Article Title
Octopus arm flexibility facilitates complex behaviors in diverse natural environments
Article Publication Date
11-Sep-2025
Zoology: Octopuses put their best arm forward for every task
Scientific Reports
Octopuses can use any of their arms to perform tasks, but tend to use a particular arm, or arms, for specific tasks. This finding, presented in a paper in Scientific Reports, reveals more about the complex behaviour these animals display.
Octopus arms are complex structures consisting of four separate muscle groups — transverse, longitudinal, oblique, and circular — around a central nerve. These four muscle groups allow octopus arms to deform in a wide variety of ways to perform a range of actions used for various behaviours, from hunting and moving, to self-defence. However, little is known about how wild octopuses use and coordinate their arms.
Chelsea Bennice and colleagues analysed 25 one-minute videos of wild octopuses, filmed between 2007 and 2015 in the Atlantic Ocean and Caribbean Sea. The filmed octopuses were either common octopuses (Octopus vulgaris) or from the closely related species Octopus insularis or Octopus americanus. The authors recorded which arms were used each time the octopuses performed one of fifteen distinct behaviours (such as crawling). They also recorded what combination of twelve distinct arm actions (such as curling) took place during the behaviour, and what combination of four distinct deformations (such as elongating) took place to perform each arm action.
The authors found that all the octopuses could deform all eight arms in the four distinct ways, and could perform all of the actions with each arm. They also found that arms on both side of the body are used equally, but that the front four arms are used significantly more often than the rear four arms (64% compared to 36%). The front arms are more likely to be used to explore the surroundings, while the rear arms are more likely to be used to move the octopus around. As a result, two actions are performed more often using the rear arms: roll, in which the arm moves underneath the octopus along the seafloor similar to a conveyor belt; and stilt, in which the arm is extended straight downwards to raise the body.
The authors say that their results are some of the first to show that octopuses use specific limbs for specific tasks — behaviour which is currently only well known in primates, rodents, and fish. They also state that their results could be used to improve robotic arms which mimic the functionality of octopus arms.
Journal
Scientific Reports
Method of Research
Observational study
Subject of Research
Animals
Article Title
Octopus arm flexibility facilitates complex behaviors in diverse natural environments
Article Publication Date
11-Sep-2025
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