Humans of the two genders have corresponding parts. Hormones control how they develop before birth. The same structures will either stay inside the body and become ovaries, or they will move down to become testicles. Another structure will become either a clitoris or a penis. Breasts either will or won't become able to produce milk.
if your guineapig has nipples means it still is a boy.
Boy guinea pigs don't have nipples.
darker nipples
no it is not
Nothing comes out f them.
its because when you are a zygote then you can either be a boy or a girl so the nipples develop anyway
Harry Styles
It could be puberty.
nipples vary in size, so yes they're normal.
girls then wants so that the boy bite and eat her total nipple
Yes they do, all mammals have them, male and female. However, male dogs usually have immature nipples. Also, depending on the amount of fur, it is possible to not be able to find their nipples.
For probably the same reason that men do. All boys start out girls whilst developing in the womb and develop nipples before they are boys.