Two of those hearts called branchial hearts sit near the gills. Their only job is to pump blood through the gills so it can absorb oxygen from the water. The third heart; the systemic heart is the main one. It takes that oxygen-rich blood and circulates it to the rest of the body, to the arms, the organs, the muscles.
Now here is where it gets extraordinary. The moment an octopus starts to swim using jet propulsion to blast itself through the water, that main systemic heart stops beating. Completely. It pauses. The reason is mechanical: when the octopus contracts its body powerfully to jet through the water, the pressure compresses the veins feeding into the heart, cutting off the blood flow. Like squeezing a straw shut.
This means that every time an octopus swims, it is essentially running on the oxygen already in its blood and tissues, with its main heart on pause. It is exhausting. And this is exactly why octopuses almost always choose to crawl along the seafloor rather than swim. Crawling keeps all three hearts beating steadily. Swimming shuts the most important one down.
Their blood is also blue, not red. This is because instead of iron-based haemoglobin like ours, octopuses use copper-based haemocyanin to carry oxygen. It works better in cold, deep water, but it is less efficient overall, which is another reason they needed three hearts in the first place.
The octopus is built completely differently from almost everything else alive. And somehow, it works.
Verify here:
https://www.smithsonianmag.com/science-nature/ten-wild-facts-about-octopuses-they-have-three-hearts-big-brains-and-blue-blood-7625828/
https://www.sheddaquarium.org/stories/eight-strange-and-wonderful-facts-about-octopuses
No comments:
Post a Comment