Visual Stimuli for the Induction of Hunting Behavior in Cuttlefish Sepia pharaonis.

Cuttlefish exhibit typical hunting behavior, including elongating tentacles against specific prey such as prawn and mysid shrimp. Cuttlefish hunting behavior involves three different actions: attention, positioning, and seizure. Hunting behavior is innate and stereotypic behavior, and it is present in newly hatched juveniles. Factors associated with prey are known to induce this behavior, similar to the sign stimulus, whereby young herring chicks imitate pecking behavior against a red dot on their parent's bill. Although the hunting behavior of cuttlefish has been described and used as an indicator to test learning and memory, details of a stimulus that can elicit this behavior remain unknown. Here, we used a variety of visual stimuli presented on a computer screen to investigate the factors that induce hunting behavior of pharaoh cuttlefish, Sepia pharaonis. We found that the appearance of prey (western king prawn, Melicertus latisulcatus) and their movement at a vertical angle of 45° are specific factors that can initiate hunting behavior. We also showed that the height of prey can attract cuttlefish and initiate hunting. To the best of our knowledge, this is the first report of a stimulus that elicits stereotyped hunting behavior by coleoid cephalopods.