Octopuses are among the most intelligent invertebrates on Earth. With approximately 500 million neurons distributed throughout their bodies, they possess cognitive abilities that continue to astonish researchers.
Unlike vertebrates, two-thirds of an octopus's neurons are located in their arms, allowing each arm to act somewhat independently. This distributed nervous system enables them to solve complex problems and even use tools.
In laboratory settings, octopuses have demonstrated the ability to open jars, navigate mazes, and recognize individual human faces. Some species have been observed carrying coconut shells to use as portable shelters—a behavior that qualifies as tool use.