breast feeding

[student16]

why cant males breast feed aswell

[jake-the-peg]

That's a good question. I'm reporting it for moving to Science where it'll probably get better answers.

It would be evolutionarily advantageous if males could breastfeed. If the mother wree killed there would be less chance of the off spring dying.

Of course males wouldn't have the biological triggers to lactate but that could happen seasonally or in response to smells etc.

The fact that we don't see any groups of mamels doing this is likely to mean that there's an even stronger disadvantage to it although what that would be escapes me at the moment.

[MargeB]

Certain 'features' can 'drop out' if not used. We still carry nipples etc but not breasts as such. I think the selection pressure for male breasts was quite high initially, because things were really tough and you needed all the help you could get in child rearing. Also, groups may have been very very small, so that there was room for this.

What is for sure is that the 'niche' that humans fell into for much of history is the 'hunter (man) gatherer (woman) niche, so probably men were not even around for much of the time to 'wet nurse'. Also, during hunting, a pair of breasts may have been disadvantageous. Furthermore, the style of the hunter gatherer community is a cooperative one, mostly for the meat sharing bit, so you would tend to have larger communities with responsibility shared around. When this happens, related women can take turns to breast feed each others' young, reducing the need for men to ever have to do this.

Might not be that, but looks like the best fit that I can see.

[Ralph]

As an aside, male pigeons breast feed their young, as well as the females. A pigeon chick weaned on the milk of both its parents will double its weight in two days.

http://www.pigeons.com/resources/facts.html just in case you think I was making it up!

[gen2]

Ralph, I think you have misunderstood the anatomy of a pigeon.  Neither the male nor the female breast feed their squabs.  Pigeon milk is produced in their crop which is situated in the upper part of their digestive tract. Reference here . No birds breast feed their young, though in most species, both parents share the feeding and care of their young.

Biologically, human males can still lactate.  What they have lost are the hormonal triggers that initiate its production.  Modern treatments (eg for prostate cancer) have stimulated the male mammary tissue to produce milk.  Presumably this will be true for the males of other mammals apart from humans if they were to be hormonally stimulated.  I know of no male mammal that naturally lactates for its young.  The reference for male lactation is to be found at wikipedia

[gen2]

Sorry, I didn't read my own references carefully enough before posting.  According to Wikipedia, it appears that there is a species of fruit-bat where the male does in fact lactate in order to share in the nurturing of their young.

Well, you learn something new every day

[jake-the-peg]

All the same there must be a strong evolutionary pressure resisting this. Not least because the bat example shows that it's possible and yet absent from all other mamals.

The hunter gatherer explanation Marge offered sounds unlikely because we're not just talking humans here.

Perhaps the point is that if a lactating female dies the males best shot at passing on genes is to abandon the brood and find another female 

[Solarjunkie]

When I was taking breast feeding classes, we were told that there were cases on record of men feeding babies - nice to see Wikipedia backing that up.