Range: Oceans worldwide

Habitat: Reefs, near hydrothermal vents, seagrass beds, open ocean, and more

Size: About 1 inch - 13 feet (2.54cm-4m) long; Up to 30 pounds (13.6kg)

Diet: Crustaceans, molluscs, fish, and other cephalopods

Threats: Fish, seabirds, seals, whales and dolphins, sea otters, and other cephalopods

Life span: Up to about two years

Transcript:

Today on Animal Fact Files we’re discussing the octopus. Octopuses, or octopodes, are classified in the order Octopoda which means “eight footed” - octopus limbs, however, aren’t called feet; octopus limbs are called arms. People often erroneously refer to these arms as tentacles, but technically speaking octopuses don’t have any tentacles! Tentacles are found in squids and cuttlefish - they’re the longer, club-ended limbs - but an octopus lacks these!

The general body shape of an octopus includes the mantle, head, and arms. An octopus’s eight arms are covered on one side in suction cups and often one of these arms acts as a means for passing on genetic material, but we’ll come back to this. Some octopuses also have fins like the dumbo octopus. An octopus’s eyes are located on its head; the head also contains an octopus’s beak-like mouth and its brain - which is the largest compared to body size of all living invertebrates.

Directly behind the head is the mantle which contains the octopus’s vital organs including the stomach and three hearts! One of the octopus’s hearts pumps blood around its body while the others pump blood to its gills. Octopus gills are also located in the mantle. In size, octopuses range from the giant pacific octopus - who can reach more than 13 feet (4m) across its arms and weight more than 30 pounds (13.6kg) - down to the smallest, the star sucker octopus, who only reaches an inch (2.54cm) across its legs!

Octopuses are marine animals that live in every ocean. They may be found from tidal areas to depths of more than four miles (6,437m). Octopuses may live on reefs, near hydrothermal vents, in seagrass beds, and even out in the open ocean.

Predators to octopuses include fish, seabirds, seals, whales and dolphins, sea otters, and even other cephalopods, but many octopuses have tricks for escaping these animals. Probably the most well known octopus defense tactic is its ability to ink. When an octopus inks, the ink is mixed with mucus which helps create the viscous ink blob that’s shot into the water through the octopus's funnel. The blob acts as a distraction to a predator and gives the octopus time to escape.

Octopuses may also quickly change color to help them blend in with their surroundings. There are also some octopuses, like the mimic octopus, who change their body shape in order to appear like other animals all together! In the end, however, most octopuses don’t live to be more than two years old as many die shortly after mating or producing offspring.

A male octopus will use a special mating arm for delivering his sperm to a female. It’s believed some males will even scoop out the reproductive material of a previous suitor before storing theirs inside the female’s mantle. Some, like the argonaut, will actually detach their mating arm and leave it inside the female octopus’s body! The female may store the sperm and use it when she sees fit.

Octopus eggs are guarded by the female who won’t eat during this time. Tiny, planktonic babies will emerge from the eggs and set off into the world on their own. Young octopuses eat small animals like copepods, but as they get older they take on larger prey. All octopuses are venomous, though only blue ring octopus is known to be deadly to humans. Octopus meals include crustaceans, molluscs, fish, and other cephalopods.

Now we’ve seen plenty of arguments in our comments sections over the years about the proper way to say the plural of octopus. If we look at Wikipedia, they list the plural as octopuses; if we dive a little deeper we see that these animals are frequently referred to as either “octopuses” or “octopodes” in scientific writing. Looking further we find that, in fact, the term “octopi” is simply wrong. “Octopus” the word is Greek in origin and saying “octopi” implies the word is Latin in origin, which is just incorrect. So, it should be clear “octopi” is universally not correct while “octopuses” and “octopodes” are both used interchangeably. So for all of you who like to stir up mischief in the comments section, just know that we all know who didn’t watch until the end of the video.

For more facts on octopuses, check out the link in the description. Give a thumbs up if you learned something new today, and thank you for watching Animal Fact Files!