I never figured it out. The real reason, guys?
2007-12-09 13:28:48 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Biology
Nipples are vestigial structures on males left over from human evolution. Women must have evolved first then slowly males are no longer needed to feed their young. Slowly the use for them disappear. But they are still there! Just like your appendix.
@Gary: No. Not true. Male rats and mice have completely suppressed nipple development.
2007-12-09 13:37:34 · answer #1 · answered by Shinya 3 · 0⤊ 0⤋
Because the default body plan in humans is female. You need to make a male and about the 8th week of gestation a hormonal surge from developing gonads do just that, though other are happening at the same time.
The structures are not accurately vestigial, because they are not used for other purposes in human males. More evolutionarily neutral and passed under the effects of natural selection.
This applies to humans, in the case we are discussing.
2007-12-09 21:59:34 · answer #2 · answered by Anonymous · 0⤊ 0⤋
because we are mammals. All mammals, male and female have nipples.
2007-12-09 21:32:34 · answer #3 · answered by Gary H 7 · 0⤊ 0⤋