There might not be “friends from out of town” amongst us, but our own neighbors are plenty strange. The more we learn about octopuses, squid and cuttlefish the more they startle us with their sheer outlandishness. A calamari appetizer when alive can maneuver with a waterjet, grapple and taste with tongue-like tentacles, bite through a finger with a beak and change colors like a chameleon. Captive octopuses routinely escape their tanks, open screw jars and solve puzzles like apes, and squid have been observed literally flying above the sea in energy-saving glides.
Now comes a new look at the outlandish eyes of the cephalopods. Octopus eyes have long been a textbook example of convergent evolution, in which two unrelated species evolve similar traits. Although humans and cephalopods are separated by many hundred million years of evolution, a human eye and a squid eye are extremely similar in form. Thus the gigantic eyes of giant squid and their cousins have long proved a mystery to scientists — why are they so much larger than those of any other creature, including other deep-sea critters? (They are huge – as big as a man’s head.)
A new study suggests that giant squid evolved giant eyes in an undersea arms race. The authors calculate that, at depths of more than a kilometer, the enormous light-gathering power of the giant squid’s eye can detect a large submerged object through its bioluminescent wake from 120 meters away. What sort of submerged object, and why would it be important for the squid to detect them? Answer: their greatest threat, Moby Dick himself, the sperm whale (Physeter macrocephalus). Much of what we know about giant squid comes from studying the stomach contents of these giant predators who can dive over a mile in search of prey.
Anti-submarine warfare is nearly as old as the submarine itself, and the proven ASW methods are made more difficult by our limited ability to peer into the ocean. Because water transmits sound so much more readily than air, acoustic research has dominated the fields on underwater surveillance and communication. Most underwater optical R&D focuses on blue lasers with intensities and colors designed to pierce wet murk.
But what if, now that Nature has once again shown the way … what if the technology developed for orbital reconnaissance were adapted to the deep ocean? Imagery spy satellites have been described as “Hubble Space Telescopes pointed at the ground,” and mount sensors designed to see through clouds and precipitation. Could powerful optical gear function in the deep ocean? Could useful domain awareness be achieved? Some bright folks are working on the idea, using clusters. No one (at least publicly) is working on underwater telescopes — why should they? It’s an outlandish idea.
Or maybe not.