Dan Belcher, a Google product manager, announced last week that the company will coat its trans-Pacific fibre-optic cables in a Kevlar-like material, usually reserved for making bulletproof vests.
Sharks have been attacking underwater fibre-optic cabling ever since it was first installed. In 1985, shark teeth were found stuck into a cable, and in 1987, shark attacks caused four segments of brand new cabling to fail. At the time, The New York Times reported: “sharks have shown an inexplicable taste for the new fibre-optic cables that are being strung along the ocean floor linking the United States, Europe, and Japan.” Scientists still aren’t sure why sharks are so into the cables, but there’s a hypothesis that they’re attracted to the magnetic fields generated by the high voltage running through the cables, Rich McCormick writes for The Verge.
The theory hinges on the fact that sharks have an ability called electroreception, which allows them to detect weak bioelectric fields generated by fish - this helps them hunt fish down in the ocean. The sharks use tiny detectors located near their nose called ampullae of Lorenzini, which look sort of like freckles, to sense even tiny changes in electrical fields in the water. So it’s possible that, despite being shielded, fibre-optic cables are emitting a weak electrical field, and sharks are getting that signal mixed up with signals from their dinner.
Or, as a shark expert from California State University, Long Beach, told Wired, they might just be curious. The coating for Google’s cables is part of a new US$300 million system that will connect the US and Japan and send information across the Pacific Ocean at 60 terabytes per second. Let’s hope the reinforcements will keep the connection safe, and also stop these cables from messing with shark behaviour. Here's an old video showing a shark attacking a fibre-optic cable, just in case you were interested: