Certain species of octopuses, namely the veined octopus, have been known to hold hands with their partners while sleeping to prevent drifting apart. As they are nocturnal creatures and live in open waters, holding hands is a way for them to create a bond and stay together in the chaos of the ocean. The gesture also ensures that they do not lose each other and can mate successfully. This behavior is also observed in other marine animals such as sea otters, who hold hands while sleeping to prevent drifting apart in the currents.