Feb. 15, 2017 - Thousands of feet below the surface of the ocean lives an animal with a lopsided lifestyle. The cock-eyed squid gets its name from its unevenly sized eyes; the larger is a bulging greenish orb. By studying video footage of this cephalopod captured by the Monterey Bay Aquarium Research Institute, researchers from Duke University have discovered the quirky logic behind the mismatch. Cock-eyed squid tend to swim in diagonal lines, keeping the larger eye facing upward. Sunlight is considerably dimmed by the time it reaches this zone, but the extra-large eye can make the most of what light does filter down. But in this case evolution was frugal: by only developing one big eye, the squid conserves resources as it grows. The smaller, less sensitive eye points downward, and can still make out the only light source from below—bioluminescence from other animals.
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Bizarre Deep-Sea Squid Has Mismatched Eyes