Abstract
<title>Abstract</title> <p>Octopuses have eight highly flexible muscular hydrostat arms, with potentially infinite degrees of freedom. Their unique morphology suggests that direct central nervous control of all motor units during free, voluntary movement is highly unlikely. Therefore, the concept of motor primitives was proposed. They simplify the almost intractable task of purposeful control of the eight arms into a more manageable set of motor building blocks that require only limited central commands. In the Mediterranean Octopus vulgaris, the motor primitives Reaching and Fetching have so far only been studied in the laboratory. The present study examines their occurrence as part of foraging behavior in the octopus’ natural habitat. Using a small observation-class Remotely Operated Vehicle (ROV), off the coast of the Croatian island of Krk (45°4´ N, 14°36´ E), we filmed O. vulgaris (N = 5) in their natural habitat. Analysis of 121 minutes of video footage showed that octopuses regularly use Reaching (1.40 ± 0.56 per minute) and Fetching (0.79 ± 0.84 per minute) movements during nocturnal stop-and-go foraging. Additionally, approach methods preceding Fetching, including Reaching, Moving, Stationary, and Webover behaviors, differed among individuals. These results demonstrate that the motor primitives described in the laboratory are also found in the natural behavior of octopuses in the wild and contribute to the understanding of arm control in complex and dynamic environments.</p>