Counterintuitive Facts (77): Why Did the Peacock's Tail Grow Until It Nearly Killed It?

I. The male peacock's giant tail is a disaster from a survival perspective. It consumes enormous energy to grow and maintain. It's heavy. Severely affects flying and running. It's bright and eye catching. Easy for predators (tigers, leopards) to spot. When escaping, that giant tail is a burden. Like running a marathon in a wedding dress. Logically, natural selection should eliminate this "suicidal" trait. Why did it instead grow bigger and bigger?

II. Darwin was initially puzzled by this too. He admitted: every time he saw the peacock's tail, he felt sick, because it seemed to violate all logic of natural selection. Later, evolutionary biologist Ronald Fisher proposed the Fisherian Runaway theory.

III. The story goes like this: Initially, a slightly larger tail might indeed represent some