Natural Habitat and Wild Behaviors of the Dwarf Cuttlefish, <i>Ascarosepion bandense</i>

The dwarf cuttlefish, <i>Ascarosepion bandense</i> (formerly <i>Sepia bandensis</i>), is a coleoid cephalopod like octopus and squid, and an emerging model organism for scientific research. Dwarf cuttlefish can change the color, pattern, and texture of their skin in milliseconds to camouflage with their surroundings and communicate with conspecifics. Their skin displays are directly controlled by the brain. Thus, observing the skin provides a window into neural processes in the brain. Despite the popularity of dwarf cuttlefish in public aquariums and laboratory research, little is known about their natural habitat and behaviors in the wild. We conducted a field study in the Batangas region of the Philippines using underwater photography, videography, and environmental measurements. We generated an image bank of the natural features in the environment, characterized the change in color profile at different depths, and surveyed the population of dwarf cuttlefish in coral reefs and silty barren environments (muck), at a range of depths, during both the day and night. All dwarf cuttlefish sightings occurred after sunset, at depths of 6-12 m, and on coral reefs. The animals exhibited multiple camouflage strategies, including complex skin patterning and adhesion of sand to their skin, as well as social skin displays in the presence of fish. Notably, despite apparent colorblindness, dwarf cuttlefish produced skin patterns with vibrant colors not recorded in laboratory settings, with some instances of apparent color matching to their surroundings. These findings challenge our understanding of cephalopod visual perception and camouflage and highlight the importance of studying animal behavior in its natural context. Our image bank and behavioral data are freely available on the interactive web tool, Cuttlebase (www.cuttlebase.org).