A peacock's tail: how Darwin arrived at his theory of sexual selection

How Darwin developed the radical idea of females' power to choose their mates despite it being at odds with his own notions of women as inferior

About 150 years ago, and "almost a lifetime" either side, Charles Darwin was beleaguered by the problem of the peacock's tail. Just the sight of a feather, he wrote in April 1860, "makes me sick!"

The plumage of the male bird represented a hole in his theory of evolution. According to Victorian thinking, beauty was divine creation: God had designed the peacock for his own and humankind's delight.