For some unknown reason, sharks want to bite undersea cables

We’ve long known squirrels are a major problem to anyone laying cable, but according to a report by the International Cable Protection Committee cable bites—by sharks and other fish—remain a surprisingly persistent problem. In the 1980s, a deep-ocean fiber-optic cable was cut four times. Researchers blame crocodile sharks for those attacks after finding teeth in the cable.

The cable protection folks really have no idea why sharks bite cables either, although some suggest it may be due to “electro magnetic fields from a suspended cable strumming in currents,” they say in their report.

Or, it's because sharks are "bitey."