Sunday, October 8th is World Octopus Day! Can you guess why this day was chosen to celebrate these cephalopods? Well, it should be pretty obvious why October was chosen, since that’s the month that sounds the most like the word “octopus”. But why the 8th? Because octopus means “eight feet”, which is the number of appendages each octopus has!
Those appendages aren’t actually feet, though. They’re arms. Though these arms are often called “tentacles”, that term technically refers to the longer, thinner specialized appendages found on squids and cuttlefish. An octopus’s arms are flexible and feature suction cups on the underside, which make it very useful for manipulating and grasping objects. These cups are extremely sensitive, and not only help the octopus hold onto things, but also allow it to “taste” anything it touches.
Octopuses are mollusks: invertebrates that lack bones and skeletons. Together with squids, cuttlefish, and nautiluses, octopuses form the class Cephalopoda. Since they lack bones, octopuses are extremely flexible and able to squish and squeeze their bodies in all sorts of ways. They can change their skin texture and color to blend in with their surroundings, looking more like a rock than an animal. They can also fit their entire bodies through holes that are barely larger than an inch in diameter to escape a potential predator.
But that’s just one of the ways these remarkable ocean creatures can deal with predators. They can also squirt a cloud of ink into the water to cover their tracks as they make an escape. If they’re forced to stay and fight, they can deliver a bite with their powerful beak that is not just painful, but venomous as well (though only one species, the blue-ringed octopus, is dangerous to humans). In the event that none of these efforts work and the octopus is attacked, it can regrow any of its arms if they are torn from the body.
Octopuses are very curious and intelligent creatures, which can cause trouble when they’re kept as aquarium exhibits. One particularly restless octopus named Otto was known to cause trouble for the staff at his aquarium, juggling hermit crabs and rearranging the objects in his tank. He even threw rocks at the tank glass and damaged it, and would shoot a jet of water at an overhead light that seemed to annoy him, causing it to short circuit. Octopuses are believed to be the most intelligent of all invertebrates, with the largest brains in comparison to their body size. They are known to engage in behavior that includes using tools, navigating mazes and problem solving.
There are over 300 species of octopus, ranging in size from the tiniest members of the genus Octopus, weighing less than 1 gram, to the Giant Pacific Octopus, which can weigh up to 150 pounds! Octopuses are secretive and elusive creatures, making it difficult to study them in the wild and even harder to get estimates on their total population numbers. It is believed, however, that climate change is having an effect on many species, due to ocean acidification, oxygen limitation, heavy metals and toxins in the water, and other climate change related issues.
Bernie’s Bonus Fun Fact: You may have noticed we didn’t use the word “octopi” to describe more than one octopus. The truth is, while many people use the plural “octopi” as the plural form of octopus, this is actually incorrect and is based on a misunderstanding of the Latin root language. The proper form is “octopuses” or “octopodes”. However, “octopi” has become so common that it is generally acc