Tech giant Google is to reinforce its undersea internet cables because sharks keep biting them.

It is going back to 100,000 miles of fibre optic cable that it owns around the globe and reinforcing it with a protective matting made with a Kevlar-based material.

Since the mid-1980s it has been known that sharks are drawn to undersea cables but it is unclear why.

Some have suggested that they are attracted by the electromagnetic signals given off by the lines which resembles the field created by fish.

In the clip below, an underwater camera caught a large shark biting a fibre optic cable in 2010.