Peacocks are male peafowl, a type of pheasant that also includes the female peahen. No matter the species of peacock, these colorful creatures boast impressively sized and patterned plumage that they fan out for display purposes. It isn't an act of vanity, though -- peacocks fan out their feathers as part of a courtship ritual to attact a mate.
Attracting a Mate
Every peacock has a look all his own, made of distinct color patterns and "eyespots" scattered across the plumage. When a male courts a female, he spreads out his tail feathers to display his colors and eyespots fully for her to see. Completely fanned out, the tail spreads behind the peacock in a full semicircle, though some peacocks have tails that are bigger than others. Ultimately, the size and the patterns of the tail help her choose whether or not she'll mate with him.
How Females Choose
When the peahen observes a peacock spreading his feathers, she chooses whether he's a suitable mate for her. Generally, the more eyespots and the bigger the tail, the better his chances are for procuring one or many mates. Particularly "attractive" males may collect several loyal mates, all of which find the qualities of his tail irresistable. Like much of nature, though, there are no sure things in peacock mating rituals, and even boasting too much of a tail can scare off potential mates.
The Size Limit
Bigger isn't always better, as far as peahens are concerned. While females typically choose males that have bigger, healthier plumage with an abundance of eyespots, they also may reject males with too much of a good thing. Tails that are too big or too flashy may be burdensome for these ground-dwelling birds, and once a peacock's plumage crosses a certain threshold, it can drive potential mates toward more modest males.
No Exact Science
As far as peacock courtship goes, plumage appreciation is relatively subjective -- there is no exact science to determine how many eyespots a peacock should or shouldn't have, or how big of a tail is simply too big for attracting females. While research suggests that there is, indeed, a threshold at which point a peacock's plumage is simply too impressive to attract a mate, and that it can likewise be too modest, the happy medium is entirely up to the peahens.
Tom Ryan is a freelance writer, editor and English tutor. He graduated from the University of Pittsburgh with a degree in English writing, and has also worked as an arts and entertainment reporter with "The Pitt News" and a public relations and advertising copywriter with the Carnegie Library of Pittsburgh.