A team of researchers working in coordination with Duke University say the massive eye of the giant squid may be a evolutionary response to its main predator, the sperm whale.

“Because the sonar range of sperm whales exceeds 120 meters, we hypothesize that a well-prepared and powerful evasive response to hunting sperm whales may have driven the evolution of huge dimensions in both eyes and bodies of giant and colossal squid,” write researchers in the publication. “Our theory also provides insights into the vision of Mesozoic ichthyosaurs with unusually large eyes.”

The team says the squids’ eyes evolved to detect sperm whales, which are known to consume the squid in large quantities. Though colossal squid are encountered remarkably rarely by people, they are thought to make up about three-quarters of sperm whales’ diet in the Southern Ocean, say researchers.

“It’s the predation by large, toothed whales that has driven the evolution of gigantism in the eyes of these squid,” said Soenke Johnsen, a biologist at Duke University, who led the research.

Big squids come in two types — giant and colossal. They can grow to weights of five adult men put together, which is comparable to a large swordfish. However, swordfish eyes are about the size of softballs, about 3 inches in diameter, say scientists, while squid eyes can grow as massive as dinner plate.

Studying samples collected nearly twenty years ago, the team discovered that the squids’ large eyes collect more light compared to animals of similar size but with smaller eyes. The extra light intake improves the squid’s ability to detect small contrast differences under the dim conditions of the deep ocean, they argue.

The basketball-sized eyeballs of the colossal squid have long been of interest to scientists. In the new study, researchers developed a computer model to look at what different-sized eyes could see at different water depths. The eye remains one of the most advanced evolutionary traits of the animal kingdom, and scientists have spent decades attempting to unlock its secrets. The eye examined by scientists remains the largest of any known animal, and it consumes a far larger proportion of the body than similar creatures, say scientists.

It remains unclear if the research has any practical application. U.S. scientists are increasingly focused on developing technology that allows for better sight in depths similar to areas occupied by the giant squid. Speaking Friday, scientists say research into the squid eyes revealed that the creature has the ability to see nearly a 100 yards underwater at depths of nearly 2,000 feet, a revelation that could lead to better underwater camera technology.

The study comes as research is underway on technologies intended to develop persistent undersea surveillance, improve mine detection, and enhance undersea warfare. Acoustic and non-acoustic sensors systems are now being explored to provide comprehensive tactical and strategic awareness in the submarine battle space, with emphasis on technologies to establish persistent undersea surveillance, improve mine detection and enhance undersea warfare.

While much of the research is currently at the component level, system-level technology demonstrations are increasing and in the long term, next-generation systems could be carried on-board naval vessels, or deployed as fixed, autonomous installations to protect fleets or ports as required, say researchers…