The octopus has brain and heart tissue.

The octopus, unlike the average animal that has only one heart, has not only 3 hearts, but also 9 brains. Of his 3 hearts, one is known as the whole body heart, which is responsible for supplying blood to the whole body, while the remaining two are known as the gills heart, which grows near the gills and is specialized to supply blood to the gills. It is also said that these three hearts are like human ventricles, except that the octopus separates them.

And the blood pumped from this heart is not the same as that of humans; the octopus's blood takes on a peculiar blue color, largely because in the cold temperatures of the ocean floor, they choose to use copper ions to transport oxygen, which turns blue when it combines with oxygen, though this also makes the octopus much less capable of transporting oxygen than vertebrates.

Octopus reproduction

Octopus reproduction in the oceans is generally concentrated in the spring and fall, when seawater temperatures are around 16 degrees Celsius. Octopus like to spawn in the conch shell, so the rope can be threaded through the red conch shell sunk to the bottom of the sea, extracted in time to catch. Autumn and winter often burrow in deeper waters in the sediment.

Octopus dioecious. The male has a specialized wrist, called the stem wrist or handing wrist, used to put the sperm packet directly into the female's coat cavity.

Every breeding season, the female octopus lays eggs, about 0.3 centimeters long, totaling more than 100,000, under rocks or in caves. The female guards the eggs during incubation, using a suction cup to get the eggs clean and stirring them with water. The female octopus needs the young to hatch 4-8 weeks after the one-time egg laying. The juvenile octopus is shaped like an adult but small, and after hatching needs to drift with the plankton for a few weeks before sinking to the bottom to hide.