Does an octopus have 3 hearts?
Yes they do!
And they also have 9 brains and blue blood.
Octopuses have one central brain and one mini brain in each arm. With all those brains, an octopus can control their arms more efficiently so it can look for food easier and quicker. Each arm can act autonomously, tasting, touching and moving without guidance from the central brain. So one arm can be exploring and feeling around, while another arm is doing something different.
The central brain which is able to take full control if it needs to is a doughnut shape and forms a ring around the oesophagus so when an octopus swallows, the food passes through the brain! That’s different!
Even though the brain in each arm sends signals back to the central brain about taste and texture, it doesn’t send any data about its location or orientation. So that means an octopus doesn’t know exactly where its arm is unless it can see it.
But how do they keep their suckers from sticking to each other? The answer is a special chemical that is secreted from the octopus skin that keeps the suckers sticking to it. That is just as well as we can only imagine what a tangled mess an octopus could get into if its legs got all tangled and stuck up!
With all that activity from eight arms and nine brains, they need a good control system! So it needs three hearts. Two of the hearts work exclusively to move the blood around, and the third heart keeps circulating and flowing to their organs.Â
Surprisingly, the third heart actually stops beating when it swims and that is why they crawl more than they swim because it exhausts them. Octopus’s blood is blue because the protein haemocyanin which carries oxygen around the octopus body contains copper rather than iron like humans do. Copper-based protein is more efficient at transporting oxygen molecules in cold or low-oxygen conditions so it is a perfect solution for life in the ocean.Â
You may have already learnt that this odd looking species is very clever. They are one of one a few species to use objects as a tool. They are great at solving tasks to get food, they can build dens and pick up stones to create shields to protect themselves. More recently video footage has emerged showing a female octopus picking up shells and other debris and throw at a male who is harassing them.
https://www.youtube.com/watch?v=wgU2jA8PQHI
They may be boneless but they are not brainless!
With three brains an octopus is quite complex and it is unlikely humans are intelligent enough to fully understand how they think.
Octopuses feel and respond to pain in a similar way to mammals and they do what they can to avoid it. They have an excellent memory and remember places they have experienced pain and don’t go back there.
They are also excellent problem solvers and thinkers, are very curious, and they plan and calculate to achieve an outcome. They can also recognise individual people, even if they are wearing the same clothes. They even learn how to do something by watching another octopus.
Octopuses also get bored so they will look for something to entertain themselves. That could mean finding something to explore or eating their arms which is a disturbing behaviour known as autophagy that happens when they don’t have any stimulation.
Yes, octopus are sentient beings.
