An important visual task for many animals is gaze stabilization. To reliably detect moving objects, such as predators or prey, or static visual features, such as burrows, animals must differentiate between their own motion relative to their environment (egocentric motion) and the motion of objects within their environment (allocentric motion). To distinguish between egocentric and allocentric motion, animals stabilize their gaze by orienting to static visual landmarks. However, in environments such as tidal creeks, orienting to static landmarks can be difficult  because of caustic flicker and conditions that cause low visual contrast. Caustic flicker is a challenge for gaze stabilization because animals may mistake the movement of light for the motion of a nearby static object. Viewing conditions that decrease visual contrast are a further challenge to gaze stabilization because they make objects harder to distinguish at a distance, giving animals fewer options for reliable visual landmarks.

How do animals in tidal creeks reliably stabilize their gaze despite the challenges posed by caustic flicker and low visual contrast? Caustic flicker modulates light intensity, making achromatic visual cues unreliable, and narrow spectral conditions reduce the reliability of chromatic visual cues. Thus, compared to achromatic or chromatic visual cues, polarized cues, such as the angle of linear polarization (AoLP) and the degree of linear polarization (DoLP), may be a relatively reliable source of information for gaze stabilization in tidal creeks. In their new study titled "Two Decapod Crustaceans, Panopeus herbstii and Petrolisthes armatus, Stabilize Their Gaze Using Achromatic Visual Cues, but Not the Angle of Linearly Polarized Light", graduate student Madison Janakis, her mentor Dr. Dan Speiser, and their collaborators, tested this hypothesis by investigating polarization sensitivity in the Atlantic mud crab, Panopeus herbstii, and the green porcelain crab, Petrolisthes armatus. Using optomotor behavioral assays, they found that both porcelain and mud crabs use achromatic cues for gaze stabilization, but neither use AoLP cues across a range of light conditions that varied in spectral width, spectral peak, and total irradiance. These findings are further evidence that although animals may benefit from using AoLP cues for gaze stabilization in visually noisy aquatic habitats, decapod crustaceans from tidal creeks seem to rely on achromatic cues for this task.