If you love sea creatures, you’ve probably heard about octopi before. But do you really know anything about them? Their fascinating characteristics may surprise you. See what ten facts we dug up for your reading pleasure below!
Octopus Facts #1: Octopi have 3 hearts!
Did you know that an octopus has three hearts? An octopus has a heart in each of its two gills and a third one that is systemic. The systemic hearts pump blood to their organs while the gill hearts pump blood through their gills. This is why an octopus can survive even if its gills are cut off.
They are best known for their suckers. These suckers are modified tentacles used to snag prey. If you ever visit the Pacific Ocean, people often comment on how proud they are of their octopus-like tentacles. Oh, the exciting times in the Middle East!
One of their favorite foods is cuttlefish. There they catch other octopi to eat and the tiny animals get their octopus DNA from their blood and the mud that encrusting their tentacles. The octopus gets all the vitamins, in particular Vitamin C, that they need from the animals they catch.
What’s interesting is that cuttlefish’ blood bears the unusual symbol of a heart, making it sort of like a cross between a heart and a snake. All other means of communication in cuttlefish are through their tentacles.
As for their amazing mummification process, they have two hearts. Here’s how scientists explain it:
“The first heart-shaped organ is mainly responsible for pump-action, moving the blood around. The second heart-shaped organ, situated just underneath the first, is responsible for the conversion of the dietary sugar in plankton into the biologically active form of plant-based glucose — adenosine triphosphate (ATP).”
When the octopus mummifies its prey, its first heart converts one glucose molecule into two, then three, … After the organs stop pumping, the result is a juicy octopus.
They are often seen in the Middle East going on hunting trips together with the boatmen. They often bring back discarded cans of tuna, which the oil in the cans is vital for the octopus to live on. They also wrap their octopus in the straw before eating it.
One of the reasons the octopus may live so long is that it outcompetes other larger cephalopods for food.
Octopus Facts #2: Most octopi are nocturnal
Most octopi are nocturnal, which means they sleep during the day and come out at night. Nocturnal animals are active when it’s dark out, which allows them to avoid predators. Only one species of octopus is known to be active during the daytime. Aquatic animals such as octopi spend most of their time either resting or closely hanging out with others of their kind, as their main diet consists of other animals such as shrimp, mollusks, and fish.
So why do octopi have eight arms and no distinct head? Octopi have no central brain but have eight notably different arms. Primarily, because of their nervous system. To explain further, it consists of specialized nerves running from the arms to other parts of the body. Apparently, octopi communicate with each other through vibrations, using arm-specific muscles.
What would you call it if there was no throat? The first and second molars are located at different positions in the upper jaw. These positions are indicated by the long and short front edges of the molars.
Have you ever heard the expression ‘pearl wasp’? This term refers to the eight antennae on octopuses’ heads, giving them a very unusual appearance. Thankfully, this isn’t dangerous, but their size may not be what you expect.
They have suckers on the end of their arms that provide nutrition to their young octopuses, more specifically the developing nervous system.
Octopuses are thought to be the only animals that need Japanese medicine to stay healthy. It’s believed that the Japanese made this claim after observing the way octopuses are able to synthesize serotonin.
Octopuses can survive outside of saltwater for long periods of time. This is due to the highly specialized nervous system that allows them to recognize their environment in the form of a clever maze. This brainpower allows them to live under almost any kind of circumstance and is believed to be why they spread uncontrollable fear throughout the world.
Octopus Facts #3: The largest octopus ever caught was 100 pounds!
The largest octopus ever caught was 100 pounds! Octopus Facts #4 is that they have 3 hearts and blue blood. Octopus Facts #5 is that they can squeeze through any opening the size of an orange. Octopus Facts #6 is that they have excellent eyesight and can see in color. Octopus Facts #7 is that they do not have bones. Octopi have been found as far South as Florida! You might have heard about Florida’s man-eating alligators. But never thought you would meet an octopus that lives in Florida! There are two other species of octopus found in Florida, the colossal Pacific octopus and the American black shrimp octopus. These octopi have a third heart. Unlike the giant Pacific octopus and American black shrimp octopus, with the mammoth American alligator as a clue, colossal octopi do not have blue blood.
One of the most distinctive features of octopuses is the eight eyes! In the Animal Kingdom, six eyes are considered normative; octopuses have eight. Their eyesight is exceptional. Even though sharks, turtles, and manta rays have eight eyes, octopuses have great eyesight! They have 16,000 photoreceptors integrated into the skin! Their photoreceptors are sensitive to light but strong enough to distinguish color!
Octopuses can see in complete darkness! They’re also in between the sharpest feline eyes. See more about their remarkable sight in our seven facts guide to octopus eyes.
Octopuses are highly intelligent creatures. Sometimes octopuses cooperate with humans and other animals to take food from other unfortunate creatures. They have a great understanding of play, grooming, tool use, communication, and intelligence. For instance, they are very fond of blowing bubbles. That skill may contribute to human understanding of them.
Octopuses can store food in their bodies, as we once did. They can survive for days without food, just like humans. A hungry octopus will eventually jump out of the water and grab whatever it can get for itself.
Octopus Facts #4: The first octopus was discovered in 1755
The first octopus was discovered in 1755 by Danish zoologist Morten Thrane Brünnich. The octopus is a mollusk, which means it is related to clams, oysters, and mussels.
Although we now know that octopi are invertebrates, we are still quite sure that Morten Brunnich was the first to discover them; as well as his identification of different species. Modern-day octopus includes both the common and the exotic varieties, letterbivalves. It is estimated that there are approximately 300,000 species of octopus worldwide.
Octopuses have a long, tubelike body, which is about the same diameter as a human head (up to 80 cm or about 2.5 inches). Their eyes are located on the sides of the head; the animal’s skin resembles clam hide. Their arms are joined using an eight-armed joint, just like the human hand, and live on its ventral (tail) side.
The overall shape of their body resembles that of a basketball, except for the octopus’ arms; they appear to belong and are skinny. Accordingly, they have sturdy and robust arms, much like that of the extensible hammers. Eight of these joints allow this type of arm to end in a formidable nail (hence its name, octopus nails). It is rather formidable for an arm to have eight joints, as in the context of weaponized tools, “eight-armed” refers to a weaponized origami-like a gun or an octopus tentacle.
Octopuses have a highly active swimming octopus nervous system. They have eight arms (not eight arms like in the hand, but eight arms forming a “basketball”-like shape), which allow the creatures to swim in any direction. Because their arms act like whips, their swimming ability is enhanced. Also, unlike armadillos and alligators, octopuses have flippers; hence, they can control their body position in the water while moving.
Portuguese fishermen spotted octopus on Easter Sunday in 1778 at the Tejo River in Portugal. They captured two specimens for experimentation, and eventually put them to use.
Octopus Facts #5: There are over 300 species of octopi! (They’re actually more abundant than mammals!)
There are over 300 species of octopi! (They’re actually more abundant than mammals!) An octopus’ beak, or mouth, is made of hard cartilage and it’s fused to the brain. The whole body is covered in a tough skin called an exoskeleton. And unlike other mollusks, the tentacles only grow a single segment, instead of two segments like other tentacled mollusks. Octopuses can walk, but they live at the top of the food chain. This makes their skin tough and resistant to wear and tear.
We all have a sense of what a tasty snack octopus would be. Think of the texture of soft-shell salted cod or soup bones in your fridge, and let me guess, it is octopi. And one of the attributes that make octopi so tasty to us humans is their incredible taste. A recent taste test of 660 octopus samples found octopus has the strongest and most complex anti-carcinogen content of any food tested to date. With an 800% safety margin, scientists credit the highly complex taste of octopus with their incredible safety.
Some octopi can change their skin color. Others have unique spots. This makes them irresistible to wrap their tentacles around. When you wrap around, the sharp outer layer of skin breaks a tiny window in your skin, allowing oxygen, carbon dioxide, and bad bacteria like E. Coli to escape and seep into the bloodstream.
They eat small organisms and provide calcium and other nutrients to their surrounding food chain. In fact, people make 63 different types of meat from the octopus.
And the octopus’ share of toxins in the environment is a bit higher than other mollusk species. They have been found in the blood of seals, mink, walruses, and polar bears, to name a few. These toxins can take a serious toll on the people who eat them.
According to the National Center for Health Statistics, in 2019, people ate 3.
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