Octopuses decorate their homes and use tools

Octopuses are surprisingly intelligent architects, collecting rocks, shells, and shiny objects to arrange around their den entrances. They don't just make things pretty; they build fortifications, carefully selecting stones as doors they can pull shut and piling debris as defensive walls. Some octopuses even carry coconut shells for miles to assemble protective shelters, a rare example of tool use in invertebrates. Their intelligence extends to problem-solving, like escaping aquariums and opening childproof bottles. With two-thirds of their neurons in their arms, each arm can "think" independently, helping them solve complex puzzles.