What big eyes you have...
Q: What animal has the biggest eye? How big? What's its scientific name?
 A: You said "has" so I bet you mean "among the species living now". The giant squid (Architeuthis) wins that contest
easily. His 25-centimeter eye (about 10 inches: not measured but extrapolated from a much smaller squid) is as large as a
human head and ten times the size of a human eye.
Figure: [Ryosuke Motani] Relative body and eye sizes.
The comparison chart of the figure shows humans and porpoises at the top. Their eye is a barely discernible speck to the
right. Squids are next to the bottom of the chart with huge, dinner-plate size eyes.
Squids and humans evolved remarkably similar eye structures-each taking routes within their totally different groups to
get to essentially the same place. Both squids and humans have eyes with single lenses, pupils, irises, and retinas even
though squids evolved eyes under water and humans in the air.
But, at the bottom of the chart, lies the all-time winner with the biggest eye of all. The Temnodontosaurs platyodon had
an eye 26.4 centimeters (10.4 inches) across. He barely squeaks out the giant squid but, nevertheless, he wins--by an
eyelash.
The Temnodontosaurs platyodon is an extinct sea reptile. These animals looked like fish and swam in the Mesozoic ocean at a slightly earlier age than when
dinosaurs lumbered the land: 250 million years ago. They were not fish but rather ocean-going reptiles.
We know their eye size by measuring fossil eye bones: doughnut shaped rings that perhaps kept their eyes in the proper shape as they pushed their gigantic,
searchlight orbs through the waters.
(Answered by April Holladay, science correspondent, May 23, 2001)
Further Surfing:
U of Calif Museum of Paleontology: eons-old reptile eyes
Museum of Unnatural Mystery: The Giant Squid
Smithsonian Institute: Search for the giant squid
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