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How Do Swordfish Catch Prey in the Ocean Depths?

Marine biologists have long been aware that some ocean predators, such as tuna and sharks, are able to warm their eyes and brains while hunting for prey in cold underwater environments. But they didn’t know why until a groundbreaking study about swordfish from the University of Queensland in Australia revealed a likely explanation. That research determined that warming of their retinas allow swordfish to distinguish light flashes associated with prey movement more accurately. This improved their ability to see moving images and track their prey by as much as 10 times, the researchers found.

Warmer eyes, better hunting:

  • It is common to find swordfish in the Pacific Ocean at a depth of 984 feet (300 m), where the temperature can be as low as 37°F (3°C).

  • Temperature “must affect transmission speed in nerves and other molecular and neurochemical processes, slowing the whole nerve response down,” the researchers said.

  • Contrary to popular belief, a swordfish’s "sword" is not used to spear prey, but used instead to slash at its prey. Once injured, the prey is easier to catch.

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More Info: New Scientist

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