Octopuses are remarkable marine animals, recognized for their diverse movement capabilities. They employ a range of strategies to navigate various underwater environments. These movements are essential for their survival, whether for hunting prey, escaping predators, or exploring their habitats. The efficiency and adaptability of octopus locomotion contribute significantly to their success in the ocean.
Arm-Based Locomotion
Octopuses use their eight arms for movement across solid surfaces. They “walk” or “crawl” by coordinating the adhesion and release of hundreds of suckers lining their arms. Each sucker creates a vacuum, flattening against a surface to form a seal, then contracting muscles to generate suction. This mechanism allows octopuses to grip and propel themselves forward, even on vertical or inverted surfaces.
The arms are flexible, functioning as muscular hydrostats, similar to an elephant’s trunk. They lack bones, relying on interwoven muscles that contract lengthwise, crosswise, and diagonally. This arrangement enables octopuses to bend, twist, elongate, and shorten their arms at any point, providing an impressive range of motion. Some species, like Adopus aculeatus and Amphioctopus marginatus, can even “stilt walk” on two arms while mimicking plant matter to avoid predators.
Jet Propulsion
For rapid bursts of speed or quick escapes, octopuses primarily utilize jet propulsion. This method involves drawing water into a muscular cavity called the mantle. Once filled, muscles surrounding the mantle contract, expelling water through a narrow, tube-like siphon. This expulsion generates a reactive force, propelling the octopus in the opposite direction.
The siphon’s flexibility allows the octopus to control its direction of travel. By adjusting its angle, the octopus can move forward, backward, or steer with precision. While energetically less efficient for sustained travel than crawling, jetting is effective for sudden acceleration, crucial for escaping threats or swift movements through the water column.
Decentralized Neurological Control
Octopus movement stems from its decentralized nervous system. Unlike vertebrates with a single central brain, octopuses distribute a significant proportion of their neurons throughout their bodies. Over two-thirds of an octopus’s approximately 500 million neurons are located within its eight arms, not solely in its central brain.
Each arm contains nerve cell clusters, or ganglia, allowing for independent control. This enables arms to initiate and execute detailed movements, like reaching or grasping, without continuous input from the central brain. The central brain typically issues higher-level commands, while the arms manage fine-tuned execution, enabling flexibility and adaptability in their movements.
Movement for Camouflage and Mimicry
Octopuses integrate their movement capabilities with their ability to change skin color and texture for camouflage and mimicry. They rapidly alter their appearance by controlling specialized pigment sacs called chromatophores and muscles that change skin texture. This allows them to blend seamlessly into diverse surroundings, from sandy seabeds to rocky reefs.
Beyond static blending, octopuses use dynamic movement patterns to enhance disguise. They might flatten their bodies and undulate their arms to mimic a flatfish. Some species, like the mimic octopus (Thaumoctopus mimicus), imitate other marine animals, such as venomous sea snakes by waving two arms, or jellyfish by puffing up their mantle. These movements, combined with body shape transformations, serve defensive purposes against predators and strategic advantages for approaching prey.