Darwin's explanation of its advantage was in terms of sexual selection: "it depends on the advantage which certain individuals have over other individuals of the same sex and species, in relation to reproduction". The kind of sexual selection represented by the peacock is called 'mate choice', meaning the process selects the more fit over the less fit, and so has survival value. In practice, the blue peafowl "Pavo cristatus" is a pretty successful species, with a big natural range in India, so the overall outcome of their mating system is quite viable.