Survival of the hottest: evolution’s fun side has been long overlooked

The theory of evolution is dominated by the utilitarian logic of natural selection: adapt or die, survival of the fittest. But consider that ‘fit’ has two meanings these days: ‘healthy’ but also ‘hot’. There is another evolutionary mechanism that scientists have taken a longer time to appreciate – seduction by the hottest, rather than survival of the fittest. It generates very different and much stranger outcomes. Perhaps even the big brains of human beings evolved as seduction devices more than survival aids.

When an animal selects a mate, it can shape the future of its species just like breeders of dogs shape different breeds. Sexual selection through mate choice is the ‘fun’ version of evolution, able to generate random, arbitrary and bizarre innovations. It has been consistently underestimated as a source of variety in the natural world.

Most popular

Gus Carter

Pensioners, it’s your turn to cough up

Ross Clark

Netflix’s Adolescence is far from perfect

Douglas Murray

Something is rotten in Stratford-upon-Avon

Birds provide the boldest examples of sexual selection. In contrast to mammals, birds are often brightly coloured, spend a lot of time singing and frequently grow crests, tails, ruffs or plumes that positively hinder their survival. These troubled Charles Darwin. If selective survival drives evolution, then how could such ornaments come into existence, let alone persist? ‘The sight of a feather in a peacock’s tail, whenever I gaze at it, makes me feel sick,’ he wrote to the Harvard biologist Asa Gray in April 1860, a few months after the publication of On the Origin of Species. He meant that his critics had a point when they said such extravagant ornamentation could not arise by survival of the fittest.

The answer he came up with was that it was the females’ doing: peacocks had elaborate trains because peahens preferred them that way.