Polarized Vision and Camouflage Dynamics in Cephalopods

Cephalopods—octopuses, cuttlefish, and squid—possess exceptional visual abilities, with high sensitivity, resolution and visual acuity. Not only do they have excellent vision, but many species also exhibit extraordinary abilities to change skin color and texture , creating dynamic camouflage displays that blend seamlessly with their environment. Despite previous studies on the topic, a longstanding mystery remains: cephalopods cannot see color, and yet are still able to match their surroundings with remarkable precision. This raises the question of how they can achieve such detailed camouflage without color vision. Here, we use optics, statistical physics, and information theory to explore both cephalopod vision and their sophisticated camouflage patterns.

First, we constructed a model that proposes a potential mechanism by which light intensity and degree of polarization (DOP) can be mapped to color/texture information. This framework integrates with new experimental measurements of neural activity in the cephalopod optic lobe performed by the Reiter lab in Okinawa, aiming to better understand how polarized light perception could be used to inform camouflage.

Additionally, we study the dynamics of pigment cells interactions on the cephalopod's skin using a simple Hamiltonian that captures camouflage skin patterns. We explore the energy landscape of the system, a process akin to spin flipping in spin lattice systems, to determine the transition probabilities between patterns. This model, still in its preliminary stages, can potentially predict the allowed and dis-allowed dynamics of camouflage patterns displayed on the cephalopod's back.

Last, we have developed an optics model to simulate the scattering of polarized light in real oceanic environments. By combining these calculations with field measurements of polarized light in the cephalopods’ natural underwater settings, we quantify the advantages of polarized light vision over color vision. Our results indicate that while both the DOP and color decay similarly in seawater, polarized light offers significant advantages in certain shallow water reflection patterns. Furthermore, polarized vision enhances contrast, facilitating the detection of small, moving objects in deeper waters.