Giant squids possess some of the largest eyes in the animal kingdom, with diameters reaching roughly 30 centimetres — comparable to the size of a football or dinner plate — adaptations that help them gather light in the deep, dim ocean.
Size and comparison
The eyes of giant and colossal squids are extraordinary in scale: measured specimens show eye diameters on the order of 25–30 cm, making them larger than the eyes of any other known animal and comparable in size to a soccer ball or a human head.
Why they are so large
Massive eyes collect more light, which is crucial in the deep sea where sunlight is extremely weak; larger pupils and retinas increase sensitivity to faint bioluminescent cues and to the silhouettes of large animals such as predators or prey moving above.
Function and advantage
Research suggests these huge eyes help detect large, distant objects and sudden flashes in near‑darkness, improving the squid’s ability to spot threats like sperm whales and to navigate the sparsely lit pelagic environment where vision remains a vital sense.
Natural history and rarity
Giant and colossal squids live in deep, cold waters and are rarely seen alive; much of what we know about their eyes and anatomy comes from specimens recovered after strandings or from predators, making each confirmed measurement scientifically valuable.