Octopuses are arguably the most intelligent form of aquatic life with a wild, almost alien-like anatomy. They are gelatinous-bodied Mollusks with eight limbs that they can use with incredible creativity to perform a wide range of tasks.
An octopus can change its skin color to camouflage itself. It also has a built-in escape mechanism that it uses to get away from predators — their infamous ink spray. It’s hard to consider octopuses as earthlings, but that’s the ocean for you. Just wait till you learn about how many hearts and brains does an octopus have.
An Octopus’s Brains
An octopus’s brain is complex, to say the least. They have the highest brain-to-body ratio of all invertebrates. This combined with their unique physiology allows octopuses to do extraordinary things. There’s no animal alive like the octopus.
How Many Brains Does An Octopus Have?
According to the Natural History Museum records, octopuses have been found to possess 9 brains. The main one is located at the center of its body, and the remaining 8 are mini-brains located in each tentacle. This allows their tentacles to autonomously carry out important functions as each mini-brain can carry out functions independently. No wonder they’re so extraordinarily versatile with their limbs.
Why The Octopus Brain Is So Extraordinary
Absolute size is certainly important when it comes to comparing the capabilities of brains, but it’s not as important as relative size — the size of the brain as a fraction of the size of the body. It’s the relative figure that suggests how much brainpower a creature is “investing” in its body.
Add their brain-body ratio to the presence of neurons in their tentacles, and octopuses have gained the ability to solve their problems with creativity, resourcefulness, and innovation, very similar to what humans can do.
Octopuses in the wild have been observed to do things like open jars, get inside containers smaller than them, open crab traps, get in and out of fishnets, hoodwink scuba divers, and poach prey from other predators. They’re notoriously good at making judgments, working with tools, and best of all, being escape artists.
Octopuses use their unique physiology and neurobiology to their fullest. They can also recognize people and can communicate by using their complex bodies to make signs and gestures.
Octopuses have as many neurons as the average dog. Their central brain is shaped like a doughnut, and it forms a ring around the esophagus. This ring holds one-third of their neurons. Two-thirds of their neurons are spread throughout their limbs. Distributing their brainpower throughout their body in this fashion gives them the ability to act independently and demonstrate intelligence in several ways.
Researchers have found that octopuses have over 500 million neurons jam-packed in their disproportionate bodies. There are roughly 180 million neurons in the central brain. Each of their limbs is connected to the central brain via an elaborate network of over 40 million neurons. Each limb also operates as an independent unit but they still work together towards the same goal.
An Octopus’s Hearts
Octopuses have one of the most unique circulatory systems on the planet, which is not surprising given that they also have one of the most unique anatomies on the planet. They have more than just one heart, but it’s for a very special reason.
How Many Hearts Does An Octopus Have?
Octopuses have 3 hearts and a closed circulatory system, which means their blood always remains inside the vessels. The 3 hearts all have different functions and work simultaneously to keep the octopus alive.
Octopuses have 3 hearts because of the copper-rich hemocyanin in their blood. This makes their blood more viscous and gooey because of which they need more pressure to push the blood throughout their body, and one heart isn’t enough for that. And since breathing is the most important function for life, the two additional hearts are placed right next to the gills to ensure uninterrupted blood flow.
Functions Of Octopus’ Hearts
The first is the systemic heart that is located close to the center of the octopus’s body and circulates oxygenated blood. The other two are peripheral or branchial hearts that pump blood through each of the two gills, and they’re located right next to the gills. The systemic heart, however, becomes inactive whenever octopuses swim, which is why they prefer to crawl more instead.
Now you may be wondering, do they need all three to survive? No. As long as the systemic heart is intact, even if one of the two branchial hearts stops working, the octopus can still make it on the other 2. It may slow down, but it will survive.
Some say that losing a heart reduces their survival chances because they need the hearts at their gills to assist with oxygenating blood. That may be the case, but losing a heart is not a definite death sentence for octopuses. It’s like what losing a kidney would be for humans.
Other Wild Facts About The Octopus
1. Blue Blood
Octopuses have blue-colored blood, and it’s much thicker than mammalian blood or the blood of other non-molluscan species. This is due to the presence of hemocyanin.
Human blood gets its red color from the iron-based protein hemoglobin. Octopus blood, however, uses a much larger copper-based protein called hemocyanin that gives it a dark blue pigmentation.
2. Toxic Ink
Ink is arguably the octopus’ most effective defense mechanism. They have an ink sac under the digestive gland that produces the ink. Contrary to popular belief, the ink isn’t toxic. But both octopuses and squids do produce venom that they can administer through their tentacles.
The ink is sprayed out through the funnels called siphons located under the octopus’s body. These funnels also help shoot the water for swimming and excrete bodily waste. Before it exits the siphon, the ink passes through certain glands that add mucus to the ink to make it thicker and create a larger mess to ward off predators. The darkness of the ink comes from a compound known as melanin.
Octopuses have special skin cells called chromatophores that can change the appearance of the skin by adjusting color, opacity, or reflectivity. Chromatophores typically store pigments like yellow, orange, red, brown, and black.
Octopuses instinctively mix the colors in just the right proportion to match the color of whatever still life forms and rocks in the ocean they’re using to conceal themselves. And those colors, more often than not, are enough to do the job.