Creature Feature: Giant Pacific Octopus
Giant Pacific Octopus Enteroctopus dofleini
“Finally, it’s my feature!”
Who has impressive size and strength, a clever mind, and stealthy shape (and color!) shifting abilities? That may sound like the next Marvel superhero... but it’s actually your friendly neighborhood Giant Pacific Octopus! Should we have mentioned the gills and tentacles first?
The Giant Pacific Octopus (also called GPO or Enteroctopus dofleini) is the largest octopus species in the world, measuring up to 20 feet long and weighing around 150 lbs. They live in the Salish Sea and other cold, oxygen-rich waters of the coastal North Pacific Ocean.
Giant Pacific octopus have 8 arms (octo means 8) equipped with suckers that act like a cross between a tongue and a brain. They can taste what they touch! Photo by Salish Sea In-Focus contest-grand prize winner Bruce Kerwin.
Cephalopod Bod
The GPO is a cephalopod, which means it has a unique anatomy. The mantle is the oval-shaped part of the body that sits on top of the head and contains the major organs. When the muscles of the mantle contract and expand, seawater is pulled into the mantle and over the gills for oxygen exchange (did you know gills work like lungs? They absorb oxygen that’s dissolved in water). Water can then be pushed out forcefully through a jet engine-like structure called a siphon. Ink can also be ejected through this siphon, making for quick get-aways in a cloud of black!
The octopus has eight arms, each with two rows of suckers that act as both tongues and fingertips. The arms contain “mini-brains:” clusters of neurons called ganglia that allow them to process sensory information on the fly. At the center of the arms is a beak with a strip of tiny “teeth” called a radula.
Clever Critters
GPOs have not only sharp beaks but also incredibly sharp minds. Octopuses are considered the most intelligent invertebrate, and they are capable of many types of learning. They can memorize visual patterns, tell different shapes apart, recognize individual humans, and even open jars.
We also know they’re quite curious. Ask any Salish Sea diver and they’ll tell you that GPOs like to tug on dive gear, only to realize there’s nothing yummy to eat and let go!
Octopus eyes have keen vision. This one is sizing up photographer, Adam Taylor, near Bowen Island, BC
This giant may be about 16 feet long and outweigh the woman diving alongside. Photo by Brandon Cole
Mother giant Pacific octopuses lay eggs in bunches, like grapes, stick them to their cave ceiling, and carefully aerate them until they hatch. Photo by Florian Graner
Social Distancing?
Shy and solitary, GPOs spend much of their time in crevices of rocks or human-made structures.
These dens are where females will lay and guard their eggs (up to 100,000 of them!). Dens are also an excellent place to hide from predators. Because they are invertebrates and don’t have bones, GPOs can slip in and out of den openings just two inches wide!
Camouflage also helps GPOs stay concealed - octopuses can quickly change color using layers of pigment cells under their skin called chromatophores.
If a predator like a lingcod or harbor seal does happen to find a GPO, the octopus can expel a cloud of dark ink before zooming off with jet propulsion from its siphon.
Lingcod prey on young giant Pacific octopus by opening their mouths fast, creating a pump that sucks the unsuspecting octopus right in with a rush of water. Photo by Jan Kocian
On the Prowl
So what’s a GPO up to when it’s not at home? The GPO is a carnivore, and at night it will emerge from its den to hunt crabs and clams. It uses its arms to crawl along the seafloor and jet propulsion from its siphon to swim and lunge after prey. You can see this in action in this month’s featured video.
After catching a yummy dinner, it will hold onto it with its suckers and carry it back to its den, where it can eat in peace. So, if you ever find yourself scuba diving and see a pile of shells and bones, you might be at the doorstep of a GPO’s hidey-hole!
GPOs and YOU
The Giant Pacific Octopus is one of the Salish Sea’s most treasured animals. If you are ever lucky enough to encounter one while exploring, be sure to treat it with respect. Also, sometimes GPOs get caught in fishing lines, nets, and crab pots. Be sure to watch out for this, and carefully free it where it was caught so it can get back to its den.