Octopuses have the most flexible appendages known in nature, according to a new study in Scientific Reports. In addition to being soft and strong, each of the animal's eight arms can bend, twist, elongate and shorten in many combinations to produce diverse movements. But to what extent can they do so, and is each arm equally capable? Researchers at the Marine Biological Laboratory (MBL) filmed 10 octopuses over many months while presenting them with a variety of challenges, and recorded 16,563 examples of these arm movements.