It is one of those curiosities of life that, once you find yourself entwined in a romantic relationship, suddenly, it seems, you've become much more attractive to those around you. All sorts of half-scientific answers have been put forward to explain the apparent phenomenon: might it be pheromones, or a sudden boost of confidence? Maybe the exercise of sex makes you more attractive? Or, maybe, some other person's willingness to shack up with you counts as a vote for your value as a potential partner?
In people, whether hooking up actually makes you hotter is up for debate. But in at least one other part of the animal kingdom having a lot of sex, or, giving the impression that you're having a lot of sex, does actually seem to result in more sex.
According to a new study by Roslyn Dakin and Robert Montgomerie, published in The American Naturalist, male peacocks will sometimes sit around making fake sex sounds, noises loud enough to be heard far and wide—a trick to make other peacocks think they're getting some.
“Whenever a peacock attempts to mate, he gives an exuberant squeal or ‘hoot’ call as he rushes towards the female and attempts to mount her,” says the American Society of Naturalists. Here's what it's supposed to look like (NSFW, due to peacock sex):
These dishonest calls are surprisingly common, making up about a third of all hoot calls in our study populations. Females are more likely to visit males after they give a solo hoot call, and we confirm using a playback experiment that females are attracted to the sound of the hoot.
The fake-sex hoot, says the BBC, may be a learned behavior: “By pretending they are mating when they are not the birds could convince females they are more sexually active - and therefore genetically fitter - than their rivals.”
With fake sex being reinforced by real sex, some males seem to have learned to keep up the ruse.