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The Secrets Hidden by Octopuses: They Have 9 Brains and Common Ground with Humans

Published February 22, 2026, 12:09
The Secrets Hidden by Octopuses: They Have 9 Brains and Common Ground with Humans

Octopuses are among the most intelligent and fascinating animals in the marine world. They have about 500 million neurons, many of which are in their tentacles, giving the impression that they have nine 'brains.' Each tentacle operates almost autonomously, allowing them to sense and taste with great accuracy. They have demonstrated memory, learning ability and problem-solving skills, can use tools and exhibit playful behavior. They can recognize people and develop preferences or dislikes. Biologically, they have three hearts and blue-green blood due to the use of copper for oxygen transport. They have the ability to change color and shape for protection or communication, while the absence of a skeleton allows them to fit into very small spaces. Their reproduction is also special, as females can store sperm.