Despite possessing only one photopigment in its retina, a feature which should render an animal colorblind, the octopus, like other cephalopods, possesses an unrivaled capacity to camouflage itself with its surroundings. A recent theory suggests that cephalopods discriminate color in their environment through exaggerated chromatic aberrations, or the focusing of different wavelenths of light at different points behind a lens, caused by morphological changes in the eye. By monitoring the blurring of different wavelengths of light upon the retina from the visual field in response to the shape of the pupil, a cephalopod can still perceive color with only one photopigment. We test this theory using conditioning to a two-toned visual stimulus and its two differently-colored halves, to look at whether strobing between the two differently colored stimuli evokes the same response as that paired to the combined stimulus or one of its halves. Evoking the response of the combined stimulus would suggest that they can see the two differently colored halves simultaneously, and that a morphological change is not needed to see two different wavelengths of light. This would present a model for color perception with one photopigment that could be explored in various other vertebrates and invertebrates previously thought to be colorblind.

Despite their sophisticated visual system, convergent and comparable in complexity to that of vertebrates, Octopus rubescens is largely nocturnal and forages mostly at night. Without visual information, their primary means of gathering information from the environment is through the sophisticated chemotactile sensory system within their arms. Octopuses blinded from lesions to their optic nerves have been observed relying on chemotactile perception of their environment with their arms fully extended to maximize their sensory range. Such behavioral profiles optimizing the acquisition of one sensory modality in the absence of another would be critical for navigating and monitoring changes within their environment. Our intention is to characterize how Octopus rubescens modifies its chemotactile range after an acclimation period of either light or darkness, simulating a natural 24 hour light cycle, and then a rapid change to the opposite lighting condition. Using 3d tracking cameras we will be able to quantify the change in the range of arm extension and overall posture that accompanies locomotion during light and dark conditions.