Species Fact Profile: Giant Pacific Octopus (Enteroctopus doflenini)

Giant Pacific Octopus

Enteroctopus doflenini (Wulker, 1910)

Range: Northern Pacific Ocean
Habitat: Coral Reefs, Intertidal Zones
Diet: Crustaceans, Fish
Social Grouping: Solitary
Reproduction: Males deposit packets of sperm in female using specialized arm called the hectocotylus.  Up to 400,000 eggs, attached by female to hard surface and tended vigorously (protecting from predators, clearing off algae).  Hatchlings - each the size of a grain or rice - hatch 6 months later.  Female dies shortly after eggs hatch due to starvation (she does not feed while tending her eggs)..
Lifespan: 3-5 Years (Wild)
Conservation Status: Not Evaluated

• World's largest species of octopus.  Adults may have an arm span of 4.3 meters and weigh 15 kilograms, though some specimens have been recorded with an arm span of 6 meters and weighing 50 kilograms.  The size of the species is exaggerated in popular culture
• Only hard part of the body is the parrot-like beak.  This allows the octopus to squeeze its body into very small crevices
• Have the ability to change the color and texture of the skin by expanding and contracting pigment sacs in its skin, both for camouflage as well as for communication
• Have been documented capturing birds from above the water surface and pulling them under to feed upon
• Predators of adults include seals, sea otters, sperm whales, and sharks; juveniles and eggs have a wide variety of predators.
• Highly intelligent, display problem solving abilities (octopuses in aquariums frequently outwit puzzle feeders), spatial memories, and ability to recognize and respond differently to different human caretakers.
• Favor cooler water richer in oxygen due to copper-based blood; may become threatened if sea level temperatures rise, limiting their habitat
• Considered a popular food item in many parts of the world; currently uncertain how fishing is impacting their numbers

Zookeeper's Journal: An aquarist I once knew told me - only half joking - that it was a good thing that the giant Pacific octopus didn't have too long of a lifespan.  With its ability to learn, if it had several decades to accumulate knowledge it would probably take over the world.  The intelligence of this species is legendary  - one of my first memories of a zoo or aquarium was actually watching a large specimen patiently and methodically work its way through a puzzle feeder, undoing layer after layer of challenge to obtain a reward of shrimp inside (and this was in the days before enrichment became commonplace for most mammals, let alone invertebrates).  This intelligence (including spatial memory), combined with the ability to squeeze through even the tiniest of gaps and the ability to travel outside of the water for brief periods, makes the octopus an annoyingly effective escape artist.  I've heard more than one aquarist tell me about the time that they came in late one evening, only to find a guilty-looking octopus caught in the act of creeping towards another tank in search of a crustacean snack.