The giant eyes of the world's largest squid seem to be specially adapted to spot approaching predatory sperm whales.
Dan-Eric Nilsson at Lund University in Sweden and his colleagues examined a photograph of an adult giant squid (Architeuthis sp.) and a full-size colossal squid (Mesonychoteuthis hamiltoni) specimen, and found both animals' eyes to measure about 27 centimetres in diameter — the largest eyes of any species. The researchers created a mathematical model relating eye size to vision. They found that the only advantage of such large eyes over smaller ones is an enhanced ability to detect large, luminous objects below ocean depths of about 500 metres.
The authors suggest that these squid evolved such eyes to detect the bioluminescence that can be created by the movement of hunting whales.
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All the better to see whales with. Nature 483, 376–377 (2012). https://doi.org/10.1038/483376d
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DOI: https://doi.org/10.1038/483376d
