Colossal squid have the biggest eyes in the animal kingdom.

Across Species 23/09/26 Sep. 23, 2026 Updated 23/09/26 Sep. 23, 2026
Underwater view of a colossal squid
Credit: ROV SuBastian / Schmidt Ocean Institute
Michael Nordine
Author
Michael Nordine is a Senior Staff Writer at Britannica, where he writes the newsletter Movie Brief. He grew up with eight cats and would like to see a Komodo dragon in the wild one day.

They don’t call them colossal for nothing. Though they aren’t the largest animal in the world, colossal squid do have the biggest eyes in the animal kingdom. They tend to measure between 11 and 12 inches in diameter, roughly the size of a soccer ball or large dinner plate. 

In addition to helping them hunt in the dark waters they call home, colossal squids’ massive eyes are equally useful when spotting predators, especially sperm whales. Their eyes face forward, giving them stereoscopic vision, and they contain light organs that allow them to see in the dark and judge distances — both between its predators and its prey.

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