So why do men have nipples?

[Wiccan_Child]

No.
platypuses has no nipples (Mail or Female)

Well, platypuses aren't mammals, so they wouldn't .

Mail horses don't have them (That I know of)

I did some research and it turns out you're right: horses are nipple-less. Go figure .

Turns out I'm right too: mice don't have nippled males .

Also some times men (and women) can be born without nipples.
Breast Cancer 101 - Breast Anatomy

True, but that's not really an example of mammalian sexual dimorphism (which I assume Naraoia was referring to)...

 

[pgp_protector]

Well, platypuses aren't mammals, so they wouldn't .

....

Platypus - Wikipedia, the free encyclopedia

There Not ?
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Monotremata
Family: Ornithorhynchidae
Genus: Ornithorhynchus
Species: O. anatinus

 

[Wiccan_Child]

Platypus - Wikipedia, the free encyclopedia

There Not ?
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Monotremata
Family: Ornithorhynchidae
Genus: Ornithorhynchus
Species: O. anatinus

Oops, how embarrassing . I could've sworn they were marsupials.

 

[pgp_protector]

Oops, how embarrassing . I could've sworn they were marsupials.

Well If I Recall correctly, marsupials are Mammals

Edit:
Marsupial - Wikipedia, the free encyclopedia
Marsupials are an infraclass of mammals, characterized by a distinctive pouch (called the marsupium), in which females carry their young through early infancy.

In zoology, an infraclass is a further subdivision of a subclass, but it is rarely used. The next rank below the infraclass would be the Order or Superorder.

 

[Hespera]

And marsupials dont lay eggs. back to class.....

 

[tansy]

The sole purpose of nipples in human males is that sooner or later they would decide that they were excellent for attaching nipple rings to.
The next question is...what does evolution have to say about the modern propensity for rings being attached to all kinds of human appendages - I would say that this practice has no possible evolutionary benefit, as it is potentially dangerous, and painful when said rings are inadvertently caught on anything.

 

[Wiccan_Child]

Well If I Recall correctly, marsupials are Mammals

Edit:
Marsupial - Wikipedia, the free encyclopedia
Marsupials are an infraclass of mammals, characterized by a distinctive pouch (called the marsupium), in which females carry their young through early infancy.

In zoology, an infraclass is a further subdivision of a subclass, but it is rarely used. The next rank below the infraclass would be the Order or Superorder.

OK, I'm just going to shush now .

 

[Washington]

deleted
​

 

[Naraoia]

Quite possibly the male nipples are linked to some gene in a way that makes them very difficult to eliminate.

That's one thing I was wondering about, but I'd like to know a bit more about the evolutionary history of male nipples before I start speculating about their persistence

But likewise, they could get bigger, because there's no reason for them to get smaller. Overall, they stay the same, no?

True. Though if they got too big, maybe they'd start costing fitness. That gives me very strange mental images.

No.
platypuses has no nipples (Mail or Female)

:o HOW IN THE WORLD COULD I FORGET ABOUT PLATYPUSES???

Mail horses don't have them (That I know of)

Now that's more interesting. (But I think you mean "male" horses. Or is it just the ones employed by the post that are nipple-less? )

Turns out I'm right too: mice don't have nippled males .

As we say where I come from: even a blind hen can find grain

True, but that's not really an example of mammalian sexual dimorphism (which I assume Naraoia was referring to)...

Sort of. To clarify: I'm interested in when male nipples arose and how universal they are. That could tell something about why they are there.

If they were present in all mammals with nipples, the most obvious explanation would be simple accident. Nipples just happened to evolve so they developed before the maleness genes kicked in, and they stayed that way either because moving them under the control of some maleness pathway would've caused a crash in the developmental program or simply because there was no reason for them to go away. If they were invented or lost multiple times, that might be a more interesting story.

I wonder if there are studies on the control of nipple development and its relationship to the nippledness of men out there

Oops, how embarrassing . I could've sworn they were marsupials.

Don't worry, it seems I forgot that they even existed

 

[LifeToTheFullest!]

Oops, how embarrassing . I could've sworn they were marsupials.

Apparently you don't watch Disney's Phineas and Ferb, or you would know that Perry the Platypus (loveable pet doubling as a secret agent) is a "semiaquatic egg-laying mammal."

 

[LifeToTheFullest!]

The sole purpose of nipples in human males is that sooner or later they would decide that they were excellent for attaching nipple rings to.
The next question is...what does evolution have to say about the modern propensity for rings being attached to all kinds of human appendages - I would say that this practice has no possible evolutionary benefit, as it is potentially dangerous, and painful when said rings are inadvertently caught on anything.

Sexual selection. Think male birds on a lek.

 

[Naraoia]

The sole purpose of nipples in human males is that sooner or later they would decide that they were excellent for attaching nipple rings to.
The next question is...what does evolution have to say about the modern propensity for rings being attached to all kinds of human appendages - I would say that this practice has no possible evolutionary benefit, as it is potentially dangerous, and painful when said rings are inadvertently caught on anything.

This could be a case of Zahavi's handicap principle

 

[Naraoia]

Sexual selection. Think male birds on a lek.

Oww, leks. Leks are more interesting than they seem.

Gosh, I had too many cool animal behaviour lectures this week.

*restrains herself from spilling all the newly-learnt interestingness*

 

[LifeToTheFullest!]

Oww, leks. Leks are more interesting than they seem.

Gosh, I had too many cool animal behaviour lectures this week.

*restrains herself from spilling all the newly-learnt interestingness*

I agree. Much to be learned about ToE studying birds.

 

[tansy]

Sexual selection. Think male birds on a lek.

Hmmm! - The mind boggles

 

[juvenissun]

I don't know if "every animal have more or less one or more useless organ". Maybe they do, maybe they don't. Non-issue really.

Why do think we should be loaded with useless organs? Please explain, I do not understand what you mean.

Useless organs have no "selective pressure". So they should simply be left alone. Thus they should be accumulated in the process of evolution.

 

[juvenissun]

I think Juv has some sort of idea he is getting at with regard to vestigial organs. I hope he will just state it clearly, rather than asking cryptic questions.

No. I don't have much idea on this issue. I am just exploring.

 

[juvenissun]

No.
platypuses has no nipples (Mail or Female)
Mail horses don't have them (That I know of)
Also some times men (and women) can be born without nipples.
Breast Cancer 101 - Breast Anatomy

So no, not ALL male mammals have nipples.

It would also be a puzzle even "most" male animals have them.

 

[tansy]

This could be a case of Zahavi's handicap principle

Yee-ees...I see what you mean..sort of - thanks for link. Hmmm...again, the mind boggles!

Which human male would have the greatest chance of survival:

a. nipple-ring wearer

b. tight jeans wearer

c. the greater-bearded heman

d. the lesser-bearded heman

e. steroid pumped-up muscled chap

f. chap with muscles well-built built from heavy labour

ad infinitum..

How would all these fare in a lek? Bearing in mind that human leks seem to occur in nightclubs, bars etc, would an alcohol-induced haze in the minds of either the females or males have any bearing..or would they all end up in mangled silly heaps where they've all locked horns as it were, and would thus be rendered incapable of reproducing?

 

[juvenissun]

Sort of. To clarify: I'm interested in when male nipples arose and how universal they are. That could tell something about why they are there.

Is nipple a definitional organ for mammals? Is it possible to milk without a nipple? Why should human have only two nipples rather than several? Or, why not just has one?