Scientists have finally figured out why the cockeyed squid is cockeyed

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The cockeyed squid lives in the “twilight zone” of the ocean, between 600 and 3,000 feet deep, where there’s very little sunlight. But that doesn’t explain why the sea creatures have entirely mismatched eyes. 

Scientists have long puzzled over why squid belonging to the Histioteuthis genus—better known as the ”cockeyed squid”—have left eyes as much as twice as big as their right eyes. Duke graduate student Kate Thomas decided to comb through 160 videos of the squid from the archives of the Monterey Bay Aquarium Research Institute to try to solve the mystery.

Thomas and her team noticed the cockeyed squid always swims at an angle, with the larger eye facing towards the ocean surface and the smaller eye looking downward. They concluded that the squid’s eyes were doing two different things at once: the larger eye, which is sensitive to dim light, looks up and scans for shadows of predators, while the smaller eye seeks out for flashes of light from bioluminescent creatures below.

Watch our video to see the cockeyed squid in action.