Of Penguin Milk and Gender

Did you know that it’s only the male penguin who produces milk for the chick?


Those who didn’t think birds made milk for their chicks, need to spend more time on Wikipaedia.

Bird milk – or “crop milk” – is higher in protein and fat than breast-milk.  It is a suspension of cells from the lining of the bird’s crop which have sloughed inwards and mingled with the juices.

Like human milk, the end product is full of IgA antibodies with various bacteria and anti-oxidants.  And like our milk, it is produced in response to the milk hormone Prolactin, which surges in birds a couple of days before the eggs hatch.  The bird stops eating when it starts lactating and the chick eats only crop-milk for the first few days.  When the adult starts to eat food again, some of this is regurgitated to the youngster too.

Not all birds make crop-milk.  We’re talking mostly about pigeons and doves. And flamingos. And some species of penguin. In pigeons, doves and flamingos, crop milk is produced by both sexes. In the penguins, it is made by the male.

How did this come about?  Maybe penguins and flamingos have a common ancestor and at some point, a gene mutation in penguins flicked the crop-milk gene onto the Y chromosone.  But if it did, why was it a good thing?  Surely only one parent doing the feeding would make the new, mutated set of genes less likely to survive?  So why did they?  Perhaps the ‘crop milk gene’ is next to a bigger, more important gene that does promote survival?  Sometimes Wikipaedia raises more questions than it answers:  I wish I know enough about the evolution of birds (and the genetic coding for crop-milk manufacture) even to speculate.

But I know what didn’t happen.  The female penguins didn’t team up, burn their wee penguin bras and announce that lactation wasn’t their thing.  The female penguins didn’t have a choice. Female penguins couldn’t choose to crop-feed, unlike human males who can choose to feed their babies.  Isn’t it handy that we can make bottles and breast-pumps? (If we were technologically advanced penguins instead, maybe we would make crop-tubes and droppers instead).  Anatomy and physiology do not define human gender roles.  Which is pleasing: hubby gets out of bed to feed Tiddler far more often than I do.

Furthermore, him being slightly stronger and larger than me doesn’t automatically mean that he is the one to do the hunting.  In fact, our technological skills render body type irrelevant in most areas: we have supermarkets and cars.  There isn’t much that women can’t do physically because we’re women, or men can’t do physically do because they’re men.

So that is that.  Men and women, through virtue of technology, should be equally good at most tasks.  There should therefore be a homogenous mixture of men and women across the task-force. Social convention is the only thing holding us back.

But – is this true?  Our body differences might not be relevant any more, but what about our brains?

On Women’s Hour recently they played a clip of some very clever teenaged girls talking about the possibility of studying physics at university.  “Oh No!” they said.  “My brain just doesn’t work that way.”

The journalist’s comment was that women dismissed hard science because they didn’t think their minds were wired up for it.

And I found myself thinking, ‘but isn’t that right?  Aren’t a lot of women’s minds genetically wired away from being good at physics, where as a lot of male’s minds are wired away from being good at languages?  Isn’t that just how things are?’

‘I mean – sure, some women are outstanding at physics – but there is a natural bias towards men, isn’t there?’

….Or is there?

And of course I don’t know the answer.  I am of a generaion who read Men are from Mars, Women are from Venus, but I never reviewed the hard evidence for that either.

It was interesting to watch Uta Frith’s Horizon TV program about Autism a few weeks ago.  She suggested that autistic males and females have difficulties in understanding other people’s beliefs and desires, but that women were more able to learn what is expected of them in social situations; to copy other people; to behave as expected. Thus women with autism are more likely  to ‘blend in’ or mask their symptoms. Many fewer women are diagnosed.

But how did the women learn this?  What is it that their brains do that the mens’ don’t?

I wonder if this is the same sex difference that makes women play the ‘martyr’ in relationships?  You know the scenario:  hubby wants to do plan A, wife wants to follow plan B, kids want plan C.  Usually something that does’t matter very much, like which TV channel to watch. Wifie lets hubby have his way without making an issue of it, or tries to mediate between the hubby and the kids. Her preference gets forgotten until after about the tenth time, when she will suddenly explode:

‘I’m always doing what you want to do….’

….and hubby denies all knowledge of there ever being a conflict of interests.  My Hubby says he assumes that if I don’t argue my corner, then I don’t feel strongly enough. I sometimes feel that I miss out because I don’t feel like arguing and it’s easier to let him have his own way.

It isn’t just me, is it?  It’s as subjective as my belief that we are better at languages but I am going to stick my neck out here:  I reckon that women are better suited to fitting in, to compromising, to being ‘people pleasers’ than men.

Is it something we have culturally picked up or are our brains hardwired that way?  Did some of the ‘people pleasing temperament’ genes jump from the Y chromosone before we had moved out of caves, in the opposite direction to the penguin’s crop-feeding ones?

If the phenomenon is real, it would be useful to know how it came about.

I have been musing a lot in this post;  I only kicked off with a fact to make my lack of evidence seem less gaping.  But it’s really not my area at all and if there are any psycologists out there who can fill in my knowledge gaps, I would be interested.

Meanwhile, I’ll finish off with some more facts. They were picked from this website.  http://ukfeminista.org.uk/take-action/facts-and-statistics-on-gender-inequality/

They don’t make easy reading for a feminist, even one who might believe in brain-based sex differences. What is responsible for such a state of affairs? I am wondering whether it is our ‘predisposition to languages rather than physics‘ or our ‘people-pleasing behaviours in a group,’ or the gender roles that still predominate in the feeding of our chicks or something else entirely that might be responsible?

Anyway:  here they are.

Only on in four UK MPs is a woman. Women are outnumbered 5 to1 by men in the cabinet.  Less than 1/4 of reporters on national daily newspapers in the UK are women.  The full time gender pay gap is 10% and the average part-time pay gap is 34.5%.  Women occupy on average 30.9% of ‘top jobs’ across 11 sectors. Research on UK media found that men typically outnumber women as ‘experts’ by 4:1 on major TV and radio programmes across channels.


 Picture:  http://www.flickr.com/photos/fliepsiebieps/5622414802/






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