Are you fascinated by the contortionists of the sea? Want to learn more about the adaptations of these amazing creatures? Today, we will dive in and learn all about octopuses. First off, the plural form of octopus is not octopi, it’s octopuses! Second, octopuses do not have tentacles, they have “arms.” There are about 300 species of octopus in the ocean. They are found in all four oceans and these carnivores occupy some really remarkable jobs, features, and skill sets. Let us dive in and explore the awe-inspiring world of the octopus.
The octopus belongs to the marine invertebrate group of cephalopods. Cephalopods include octopus, squid, cuttlefish, and nautilus. Some key characteristics of the cephalopod group include their possession of protruding arms (known as tentacles for some cuttlefish and squid species), the ability to shoot or squirt ink, complex eye structure, and three hearts (with some exceptions.)
For the case of the octopus, their eight protruding appendages are called arms. This is because their arms have suckers along the entirety of the appendage. In the case of tentacles, like on squid and cuttlefish, they have powerful, large suckers only towards the bottom of the appendage—this makes them tentacles rather than arms. Squid and cuttlefish have two tentacles in addition to eight arms.
Eight Arms, Nine Brains, and Three Hearts
Photo Credit: Discover Magazine
The arms of the octopus are one of its greatest adaptations. Out of all of the neurons that the octopus contains, two-thirds of them are found in the body including the arms. These eight arms have an enormous amount of control as well as the ability to touch, “see,” and taste. Due to the high amount of neuron activity and power within the octopuses’ arms, they can still move and grip if (unfortunately) removed or dismembered from the body. Another example of a similar process is seeing a lizard’s tail move when it is removed or cut off from the body.
What does the octopus do with nine brains?! When we think about it, it’s simple. The octopus has one central brain for its nervous system, and it has a smaller brain for each of its eight arms. This establishes the ability the arms have to feel with accuracy, and move, grip, and serve as valuable extensions for the octopus.
When it comes to blood, the octopus is EPIC! Their blood actually appears blue. This is because their blood has a high concentration of copper; giving it that famous blue tinge. With three hearts, there is a lot of blood pumping to help octopuses function successfully in the ocean. Two out of the three hearts pump blood to the gills for breathing and respiration and the last of the three hearts pumps blood to the body, including the arms.
Fun fact: The octopus can propel backward in short bursts. This comes from its respiration. Octopus use their set of gills to breathe in oxygen and use their siphon to exhale. When they exert pressure and increase the speed of their inhalation and exhalation, they can use this jet propulsion to push their bodies backward! (Birch Aquarium).
Smart, Beautiful, and (a Little) Shy
You may have heard stories, watched videos, or even witnessed the exquisite nature of octopuses. They are intelligent, elusive, mysterious, and masters of every form of camouflage. Their very existence relies on the fact that they can hide, manipulate their body appearance and shape, and defend themselves in powerful and gruesome ways.
Photo Credit: NBC News
Octopus intelligence has been measured by many scientists and researchers. There is no question that they are one of the smartest creatures in the sea. Octopuses have been seen using tools to break food and open crevices. Watch a video here of an octopus using a tool to eat a crab. Tools are important for the octopus as they are carnivorous predators. They will eat smaller fish, squids, many crustaceans, other octopuses (or their same species, making them cannibalistic), and worms.
In addition to their use of tools, octopuses have been known to have an extraordinary memory. There have been studies that show that octopuses can remember puzzles, mazes, and even people! They have an outstanding degree of recognition and have even developed relationships with certain people and have been known to “play” with others (National Geographic).
The octopuses’ instinct to hide is one of great measure. They are the true “masters of disguise.” Being invertebrates and having the capability to change colors, textures, and shapes; they can transform their appearance into just about anything. They use their papillae to change forms and have been seen mimicking the shape, color, texture, and even movement of other sea creatures. Additionally, deep-sea octopuses have bioluminescence. Bioluminescence is the emission of light by an organism.
Photo Credit: Skillshare Projects
If they are hunting or defending themselves, they will use a toxic ink squirt to survive or eat. The ink that they can squirt causes their prey or predators to become disoriented, paralyzed, and sometimes suffocate. The mixture of mucus and melanin is so strong that it can even suffocate and kill the octopus itself if it does not escape from the ink cloud quickly.
Here for a Good Time, Not a Long Time
The lifespan of the octopus is usually not long. On average, they will only live for 1-2 years. By the time they are ready to mate and reproduce, many situations and factors can cause death for octopuses.
For the males, their lives are often ended by the female herself during the mating process. Generally, the females are much larger than males and the females can envelop, kill, suffocate, crush, or devoir males for food during or after the mating process. Talk about female power, watch out!
As for the females, they often die after laying their eggs. Their body goes into a suicidal mode where they slowly but surely waste away and perish. Generally, this happens right as the eggs hatch. This is similar to what happens to salmon after spawning. With new life comes death for some creatures in the ocean, but I hope you can see the beauty and purpose for every life in the sea.
If you want to learn more or watch these creatures in action, click on this informative video by National Geographic here. Thank you for reading this blog post. Stay tuned for another blog post soon where we will learn more about a couple of specific species of octopus. Have a great week!
Written By: Bailey Higa