Science shows that octopuses have three hearts and nine heads. The horseshoe crab is called a "living fossil". It still retains its ancient and primitive appearance from more than 400 million years ago. The horseshoe crab blood is blue, which is the heart of the gills and the venous blood of the gills of the horseshoe crab. At this time, the horseshoe crab Oxygen in the crab's blood replaces carbon dioxide, greatly increasing the vanadium content in the blood, which makes the blood blue. The painless bite of the blue-ringed octopus paralyzes its prey and injects deadly venom. Even humans are not safe. These amazing creatures are so good at hunting that they are considered one of the deadliest creatures in the ocean.

The animal world is always full of surprises and fun things to explore. The heart is one of the organs of most animals and one of the most interesting to zoologists. Not all animal hearts are like human hearts, and each animal's heart may be different, even more so than we think. The fairy wasp is a small insect of the Hu family, usually between 0.5 mm and 1.0 mm in length. Elf bees are the world's smallest flying insects, measuring only 0.139 mm. Their lifespan is short, usually only a few days. Octopuses are simple creatures made of tentacles and ink sacs. That's wrong! CNET looks at the most interesting things about octopuses. Not only do they have three hearts and nine brains, they may be smarter than humans and can even predict the future. An octopus has three hearts and nine brains. The large heart supplies blood to the entire body. Two smaller hearts supply blood to its gills. Another brain is located in the head, and the eight brains are distributed on the eight tentacles, so it can flexibly control each tentacle, far exceeding the human ability to control hands and feet!

The squid is a cuttlefish, and its blood is turquoise. It is precisely because of this special blood that it had to evolve three hearts, because the copper protein in the blood has the ability to carry oxygen. It is much lower than the iron-containing protein, so it is starved of oxygen. Two of the three hearts are in the gills, which can speed up blood flow and make up for the lack of oxygen. The fairy wasp has the smallest heart of any known animal and requires a microscope to see. Their heart is not as muscular as a human's but is a thin tube running along the back with no veins or arteries. These tubes beat rapidly periodically, pumping blood throughout the body.