When I was in sixth grade, our class got to spend a week at the Vancouver Aquarium. It was a fantastic experience; we got to play our flutes for the belugas, feed the sea otters, and spend a week of school at an aquarium. One thing we did miss out on, however, was seeing a giant pacific octopus. The aquarium had one, named Kirby (I think), but the week before we were there a small crack was left on one of the seals to the tank, and Kirby managed to pull himself through. This was a poor choice, as he then fell onto the ground and died, devoid of life-sustaining water.
Giant pacific octopi are found, unsurprisingly, in the Pacific Ocean. They are found as far as the Aleutian Islands in the north and in the Baja California region in Mexico, to the South. They are also found in the eastern Pacific Ocean, as northeast as Japan. They usually hang around tidal pools and don’t tend to go below 110m. They prefer habitats that have soft substrate with rocky areas that the octopi can den in. They also like living near kelp forests, and in waters measuring between 7 and 9.5 degrees celsius, as they are cold-blooded and thus rely on environmental temperatures for their metabolism.
Giant pacific octopi are aptly named; they are the largest species of octopus, with some specimens reportedly weighing up to 272kg and measuring 9.6m in radius. More normal sizes are from 15 to 50 kg, with radial armspans of 4-6m. They are usually reddish, but can change colour if they feel threatened. Of course, being octopi, they eight arms, and have a mantle which contains the octopus’s organs, brain, and eyes. Though they can propel themselves at speed of 25 mph, octopi prefer to move slowly, using their arms to crawl along the ocean bottom.
Pacific octopi eat a variety of seafood, including, shrimp, shellfish, lobsters and fish. The octopi deposit any bones or shells outside their dens into piles called middens. From looking at middens, researchers can decipher what the octopus has eaten. They have very good vision, and use this to hunt and stalk their prey, often camouflaging themselves to jump their meal. They usually grab any prey item with one of their arms and then biting it with its hard beak. An octopus’s beak is the only hard part of its body – if it can fit a beak through an opening, it can squish the rest of its body through.
Octopi are known as very intelligent animals. Their brains have folds, a sign of neuronal complexity. They can solve basic puzzles, use tools, and even recognize different people that they’ve had lots of contact with. In fact, octopi are considered intelligent enough to likely have sentience, and thus are protected by welfare laws in some countries, like the UK and Australia.
Though I didn’t get to see Kirby as a kid, I have since been to the Vancouver Aquarium, and seen the new giant pacific octopus there. They are super cool looking animals, and are probably one of my favourite species of invertebrates.
Cover Image by User:Bachrach44, CC0, via Wikimedia Commons