What male mammals have nipples?

Question

Are there any male or female mammals that don't have nipples?

Answer 1

All male land mammals have nipples -- cats, dogs, pigs, horses, squirrels, rats, monkeys, apes, porcupines, raccoons, weasels, bats, sheep, deer, elephants, etc.

I'm not certain about sea mammals -- dolphins, whales, seals/sea lions, and otters. Female cetaceans (dolphins and whales) have their nipples inside a kind of enclosed slit that tucks in like the wheels on an airplane; when their young nurse, the nipple extends from this slit and the baby connects to it, nursing underwater (which is quite a trick!)

Female marsupials, which are in the class mammalia (but are not placental mammals), have nipples in the pouch; when the infant is born, it creeps up the mother's pouch and connects to a nipple where it suckles till it has developed enough to be at least partly exposed. I don't know whether male marsupials have nipples, considering that they are inside the female's pouch.

The only mammals I am aware of that do not have nipples (male OR female) are the monotremes, which are the egg-laying mammals: the platypus and the echidna. These very primitive mammals have mammary glands, but they release milk through pores in the skin; the young lap this up from the mother's body without having a nipple per se to latch onto.

Answer 2

Because when humans form in the embryo they all begin as female. It isn't until the Y chromosome is activated that the embryo becomes male. The nipples are still there because there is no need to get rid of them after this event. (Or, if I am wrong about when the nipples form...) Then because nipple formation is coded for by a gene that is turned on during some point in embryo development. The only way for there NOT to be nipple formation, is if there was some gene on the Y chromosome which would result in a protein to cancel/inhibit the protein formation coded for by another gene leading to nipple formation. There is no reason for the body to spend all of the energy creating these proteins just to inhibit something that isn't harmful to the male. If it doesn't harm them why spend the energy to get rid of it?

Answer 3

Uh, I just checked and I have nipples on my chest. Does that count? I think you are wanting to ask if any males have functioning mammary glands, which fortunately in my case they don't.

All mammals have nipples, its just that the females that have functioning mammary glands for the offspring to suckle on.

Answer 4

All do...it is part of the development of the reporuductive system that happens after the initial physical development of the body.
The few odd-ball mammals maybe exceptions.

Answer 5

All male primates (including humans, obviously) have nipples. They are the only male animals that do.

Answer 6

all male mammals have nipples

Answer 7

Monkeys

Answer 8

neather male nor female duckbill platypuss and echidna have nipples. they are monotremes. all other mammals have nipples, both male and female.

Answer 9

No only the females have nipples so she can feed her young

Answer 10

Whales secrete a very thick milk and the calf swims along side and gulps it up. I saw this on discovery.