Octopuses are captivating marine creatures known for their remarkable problem-solving skills and camouflage abilities. They thrive in diverse marine environments, from tiny reef dwellers to massive, cold-water inhabitants. This variety prompts the question of which species holds the title of the world’s largest.
The World’s Largest Octopus
The title for the biggest octopus belongs to the Giant Pacific Octopus (GPO), scientifically named Enteroctopus dofleini. This designation is based primarily on the animal’s weight, which is the standard measure of size for these soft-bodied cephalopods. The GPO is consistently the heaviest species encountered by researchers and fishermen. Its tremendous body mass and thick arms contribute to its reputation as a true leviathan of the North Pacific.
While some other octopuses might occasionally achieve a greater length due to their slender bodies, the GPO is unrivaled in overall bulk. Its sheer scale makes it a significant predator within its ecosystem.
Record-Breaking Measurements
Typical adult Giant Pacific Octopuses generally weigh between 33 and 132 pounds (15 to 60 kilograms). Their arm span, measured from the tip of one arm across the central body to the tip of the opposite arm, commonly reaches between 14 and 20 feet (4.3 to 6 meters). These average dimensions already make it an impressive animal.
Record-breaking specimens, however, present a far more startling picture of this animal’s potential size. The largest reliably measured octopus, which was weighed while still alive, was recorded at 156 pounds (71 kilograms) with a total length of approximately 13.1 feet (4 meters).
Anecdotal accounts describe much larger, unverified individuals. These reports suggest maximum sizes that are truly colossal, including one estimated to weigh 600 pounds (272 kilograms) with an arm span of 32 feet (9.75 meters). These extreme measurements represent rare outliers and are the subject of ongoing scientific discussion.
Deep-Sea Habitats
The Giant Pacific Octopus is found throughout the coastal waters of the North Pacific Ocean. Its range extends from Baja California, along the western coast of the United States and Canada, and across the Pacific to Japan, the Russian Far East, and the Korean Peninsula.
These octopuses thrive in colder, oxygen-rich waters, preferring temperatures generally around 7 to 9.5 degrees Celsius. They occupy a vast vertical range in the ocean, from shallow intertidal zones to extreme depths.
The species is commonly observed in relatively shallow coastal waters, often residing in dens among kelp forests and rocky crevices down to about 360 feet (110 meters). However, individuals have been documented in the abyssal zone, recorded at depths exceeding 6,600 feet (2,000 meters).
Other Notable Giants
The only other species that rivals the Giant Pacific Octopus in size is the Seven-Arm Octopus (Haliphron atlanticus). This species is considered the second-largest octopus, and in terms of length, it can sometimes approach the dimensions of the GPO.
The largest specimen recorded had an estimated mass of 165 pounds (75 kilograms) and a total length of about 11 feet (3.5 meters). This animal is typically less bulky than the GPO, possessing a more gelatinous body structure.
Unique Anatomy
Its peculiar common name is due to a unique characteristic in males. One of the eight arms, specialized for reproduction, is coiled in a sac beneath the eye, making the male appear to have only seven appendages.