The ocean's deepest waters contain an acoustic superhighway that whales mastered millions of years before humans even knew it existed.
A blue whale’s call, pitched so low it sits below the threshold of human hearing, can travel 1,600 kilometres through the ocean’s deep SOFAR channel — a natural acoustic tunnel discovered by the US Navy during the Second World War that whales had been using for millions of years before we found it.
Lachlan Brown