October 8 is International Octopus Day—so we thought we’d celebrate with some “tenta-cool”  facts about our favorite cephalopod species.

How big do giant Pacific octopus get? 

Giant Pacific octopus are the largest octopus species in the world. The record for the world’s largest octopus was 30 feet across and more than 600 pounds! The average giant Pacific octopus will grow to about 16 feet across and 110 pounds. Even though they can get very large, giant Pacific octopus can shrink way down, squeezing through any hole larger than their beak—the only hard part of their body. 

giant Pacific octopus Edmond and two sea stars
Edmond, the Aquarium's newest octo-resident joined us this summer. He is very small.
How long do giant Pacific octopus live?

For such fascinating species, giant Pacific octopus live a relatively short life span. In the wild, they live only between three to five years. They can live slightly longer in captivity, where they don’t have to worry about predataion. Giant Pacific octopus’s life spans are tied to their breeding cycle, with both males and females dying soon after breeding.

How do octopus change color?

Giant Pacific octopus are usually a reddish-brown color, but—like other cephalopod species—they have the ability to change their skin color thanks to special skin cells called chromatophores. These cells help the animals blend in with their surrounding environment of corals, plants, and rocks. They use this camouflage ability to catch their prey by surprise—hiding in wait and using jet propulsion to jump out at passing prey and catching them with their arms. 

octopus playing with puzzle box
An octopus playing with a puzzle box.
How can you tell a male and female octopus apart?

Take a look at the octopus’ third arm counting clockwise when looking straight down on top of him. Males have no suckers toward the tip of it. This is what is used to deliver sperm packets to the female. Also, if you took the time to count them, female giant Pacific octopus have about 100 more suckers on their arms than the males—up to 2,240 of them!

That's a lot of tentacles.
Is it “octopuses” or “octopi”?

We turn to our friends at Merriam-Webster to answer this one—and the answer is: it’s complicated. There are THREE main plurals for “octopus” that each come from the different ways the English language adopts plurals. Octopi, the oldest plural of “octopus,” comes from the belief that words of Latin origins should have Latin language endings. Octopuses is the English ending for a word that has been adopting into the English language, and then there’s octopodes, which stems from the belief that “octopus” is originally a Greek word and should have a Greek ending. Here at the Aquarium, we use “Octopuses” if they are different species. But if it’s two members of the SAME species, we say “two octopus.” 

When are the Aquarium’s octopus most active?

Octopus are generally nocturnal. But senior aquarist Bill Murphy, who cares for the octopus and the Olympic Coast exhibit, says the octopus at the Aquarium are reliably active during meal times. That happens midday five days a week. Occasionally, the octopus are offered puzzle boxes with crab inside and that can rile them up a bit. And sometimes the octopus are just feeling their oats and explore their exhibit. 

Celebrating Octopuses!

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