Octopuses are one of the most interesting, mysterious and intelligent creatures in the world. Here are 30 interesting facts about these amazing animals.
1. Octopuses have three hearts. One of them deals with pumping blood throughout the body. The other pumps blood through the gills. The third stops working when it floats. For this reason, octopuses get tired quickly and prefer to crawl.
2. About 300 species of octopus have been discovered so far.
3. A newborn octopus is the size of a flea.
4. The oldest octopus fossil discovered is 296 million years old.
5. Octopus wrestling was a popular sport in the 1960s. The competition was a fight between a diver and an octopus in shallow water. Even the world championships in this discipline were organized in the United States.
6. Live octopus is eaten in Korea. This "delicacy" is called sannakya.
7. Many countries have banned octopus surgery without anesthesia. This is related to the intelligence of these animals.
8. They don't have 8 arms, they have 6 arms and 2 legs.
9. Hapalochlaena is the most dangerous type of octopus. They can kill a person with one bite.
10. Octopuses prove that size doesn't matter. Their brain size is comparable to a walnut. They are considered the most intelligent invertebrates.
11. A hungry octopus is able to eat its own arms.
12. They live relatively short. Some species reach as little as six months. The largest ones can live for 5 years.
13. The mimetic octopus is able to resemble 15 other marine animals, such as snakes and stingrays. It was discovered in the mid-1980s by photographers.
14. They move with elegance, but unlike most animals, their movements have no rhythm.
15. The largest documented octopus weighed 71 kg.
16. Large octopuses are able to catch and kill some types of sharks.
17. Animals have chemoreceptors in their suckers. Thanks to them, they are able to feel the taste in the process touch. There are over 10,000 taste buds on the tentacles.
18. Due to the high amount of copper, the octopus' blood is blue.
19. The skin of an octopus can change its color 177 times an hour.
20. In 2008, an octopus with 96 tentacles was caught in Japan.
21. All octopus species are venomous to humans. Only one of them poses a deadly threat.
22. One way to defend against a threat is to blend in with your surroundings. Another ability is to change color or spray a black substance.
23. The largest species is the giant octopus. Its tentacles reach a length of up to 4 meters.
24. These animals are dioecious.
25. The octopus has no bones (the only hard part in their body is a parrot-like beak and a lump of cartilage surrounding the brain), so this allows them to pass through a hole that is 4 times smaller than their own size.
26. An octopus has rectangular pupils.
27. The octopus always keeps its "house" clean by "sweeping" it with a stream of water from its funnel and placing the rest of the food in a special place nearby.
28. Octopuses are intelligent invertebrates that can be trained, remember their owners, distinguish shapes.
29. The personal life of these sea creatures is not very happy. Males often fall prey to females, and they rarely survive postpartum and condemn their offspring to an orphaned life.
30. When the water temperature drops, octopuses adapt to it by changing their set of RNA and proteins produced in the cells of the nervous system.
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