peacocks are not born with their fancy tail
They don't have fancy tail feathers because they're born with them. Male peachicks do not begin to grow their showy trains until they are about three years old. In fact, because peachicks are nearly identical to their mothers, it's difficult to tell their sex. The males will begin to change color to their vibrant blue around the age of six months.
In 1931, a scientist decided to undertake an experiment in which he raised a monkey as if it were a person.