Octopus can use odor plumes to find food

Odor-plume-guided navigation, tracking an odor plume to its source, is a primordial behavior used by most animals to search beyond the visual range. Here we report the first laboratory observations of octopuses performing this behavior, demonstrating that they can use odor plumes to find food. In a three-station discrimination task carried out in the dark, octopus showed a strong preference to move upstream towards the food-baited target, supporting the hypothesis that they are performing odor-guided search. When seeking a single baited target, also in the dark, octopuses not only preferred to move upstream towards the food source, but they also displayed characteristic motions associated with odor-gated rheotaxis, a commonly used odor tracking strategy used by many animals, which includes pausing, switchbacks, and across-stream redirections to the bait. Additionally, when approaching single baited stations the octopus often made reactive fast lunging motions. The observation of these fast arm-aligned motions (FAAM), taken together with the observation that the octopus did not have a characteristic body axis orientation to the bait, as would be expected if bilaterally symmetric organs such as the olfactory pits guided this behavior, supports the hypothesis that the suckers are the primary chemosensory organs driving octopus odor-guided behaviors. Currently, there is uncertainty about the function of the olfactory pits. Our work suggests that their role is perhaps exclusively in mediating reproduction and appetite.