Octopuses are captivating marine inhabitants, known for their intelligence and adaptability. These soft-bodied cephalopods range widely in size, from tiny creatures to immense giants. This diversity often leads to questions about which species holds the record as the largest ever found.
The Giant Pacific Octopus: The Reigning Record Holder
The Giant Pacific Octopus (Enteroctopus dofleini) holds the record as the largest octopus ever found, recognized globally for its impressive mass and arm span. Adult Giant Pacific Octopuses typically weigh between 15 to 50 kilograms (33 to 110 pounds) with an arm span reaching 4.3 to 4.8 meters (14 to 16 feet). The largest individual reported weighed 272 kilograms (600 pounds) and had an arm span of approximately 9 to 9.14 meters (30 feet). However, the largest scientifically documented live specimen had a total length of nearly 4 meters (13 feet 1 inch) and weighed 71 kilograms (156 pounds).
This species inhabits the coastal waters of the North Pacific Ocean, ranging from Korea and Japan across to Canada, the United States, and Mexico. They thrive in chilly waters, found from shallow intertidal zones down to depths of 2,000 meters (6,600 feet). Their significant size is partly attributed to their relatively long lifespan for an octopus, typically living between three to five years. The Giant Pacific Octopus’s ability to efficiently convert consumed energy into body mass also contributes to its substantial growth.
Understanding Octopus Measurements: Arm Span vs. Weight
Measuring octopus size is complex due to their soft, flexible bodies. Scientists primarily use a few key metrics: total arm span, weight, and mantle length. Arm span is measured from the tip of one arm to the tip of the opposite arm when stretched out, providing a sense of the octopus’s overall reach. Weight offers a measure of the octopus’s bulk or mass.
Mantle length refers to the measurement from the midpoint between the eyes to the posterior end of the mantle, which is the main body sac containing most of the organs. These different metrics can lead to varying interpretations of “biggest,” as some species might be heavier but have shorter arms, or vice-versa. While arm span gives a visual impression of size, weight can sometimes be a more accurate assessment for live specimens.
Beyond the Largest: Other Notable Octopus Giants
While the Giant Pacific Octopus is the largest, other octopus species also reach impressive sizes, showcasing the diversity within these marine invertebrates. One notable giant is the Seven-arm Octopus (Haliphron atlanticus). This species is considered one of the two largest known octopuses, with estimated maximum total lengths of 3.5 meters (11 feet) and weights up to 75 kilograms (165 pounds). A particularly large, incomplete specimen found weighed 61 kilograms (134 pounds).
The Seven-arm Octopus gets its name from a unique characteristic in males: one of their eight arms, specifically the hectocotylus, is typically coiled in a sac beneath the right eye, making it appear as though they only have seven arms. Other large species include the Frilled Giant Pacific Octopus and the North Pacific Giant Octopus, both subspecies of the Giant Pacific Octopus, along with the Maori Octopus and the Southern Red Octopus.