The first great energy transition: how humanity gave up whaling

The modern oil industry was born in 1859, yet it would take more than 100 years - and the near-extinction of a species - before it replaced blubber. As we now seek to replace oil in turn, are there lessons to be learned?

Humpback whales can rhyme. Their songs are made up of individual themes, phrases and sounds - many of them ending similarly. These are repeated in patterns that create rhythms and structures. To human ears, the songs are a series of grunts, groans, sighs, burps and squeaks. But they are arranged by the whale in a highly elaborate manner.

The songs change over time, too: themes develop and are replaced, and phrases shift until every few years a completely new song emerges. Whales also adopt the songs of other whales - like a pop hit that everyone starts singing.