…and this is a 
Pregnant? Feeling bloated?
Category: Organisms
Posted on: March 23, 2007 10:00 AM, by PZ Myers
Here's a picture to make you feel relatively fortunate, from the April 2007 issue of Natural History:
Naked mole rats are odd little mammals in which only the queen of the colony gets to breed. The point of this picture is that even when not near the end of their term of pregnancy, they are recognizably distinct from other rats in the colony — they tend to be much longer. The reason is that the hormones during pregnancy, and probably also the physical stresses on their body, induces the lumbar vertebrae to actually grow longer. Humans, fortunately, do not grow a couple of inches vertically with each child.
Comments
These mole rats repress breeding in other members of the colony by forcing them to eat feces laced with birth control chemicals.
Also, they are diploid, so do not have the added kin-selection r-values of the haplodipolid bees/ants/wasps ... but since they are son inbred, it turns out that an individual female is more closely related to her potential sisters than to her potential offspring. Thus she is more willing to help her mother raise more sisters.
But most important of all, they eat a lot of ROOTS, and they have the same physical morphology as the robust Australopiths, who also (I believe) at a lot of roots. So nake mole rats (and other mole rats) are an excellent model for a key moment in human evolutionary history ... the adoption of Plant Underground Storage Organs as a fallback food.
(Sorry, I get excited about naked mole rats)
Posted by: Greg Laden | March 23, 2007 10:09 AM
"Son inbred"???? Wow, that was quite a Freudian Typo ..... but since it could be correct I'm not going to suggest it be changed...
Posted by: Greg Laden | March 23, 2007 10:11 AM
"Humans, fortunately, do not grow a couple of inches vertically with each child."
Unfortunatly, I LOST some height with each child...but my feet got bigger.
I wouldn't have minded so much gaining a little height. :-)
Posted by: Teresa | March 23, 2007 10:18 AM
How long do the size increases last? Is the new bone permanent or does it leach away like osteoporosis when the hormone levels revert to normal? If it's permanent, that would imply that older queens tend to be longer, no?
Posted by: Tom Boaz | March 23, 2007 10:42 AM
The reason is that the hormones during pregnancy, and probably also the physical stresses on their body, induces the lumbar vertebrae to actually grow longer. Humans, fortunately, do not grow a couple of inches vertically with each child.
Vertical inches, no. Cup sizes, yes.
Posted by: Molly, NYC | March 23, 2007 10:51 AM
"they have the same physical morphology as the robust Australopiths"
uh...huh?
Posted by: CCP | March 23, 2007 12:13 PM
Yeah, but do you have a naked mole rat T-shirt? Or plush toy?
Posted by: NJ | March 23, 2007 12:19 PM
I'd vote for getting a couple of inches taller with each pregnancy, myself. Being short often sucks.
Posted by: Carlie | March 23, 2007 1:03 PM
More like unnatural history.
Zing.
Posted by: Two Sheds | March 23, 2007 1:14 PM
Ouch.
If that french feminist (can't remember her name) ever fulfill her dream of medical technology enabling gestation inside males willing to experience it ... I'm no longer willing. It's my body and I say NO. :-)
Posted by: Torbjörn Larsson | March 23, 2007 1:41 PM
I'm thinking I probably shouldn't show that pic to my pregnant officemate, here.
Posted by: Eamon Knight | March 23, 2007 1:48 PM
Actually, that would be kind of cool if women gained a couple inches with their first pregnancy, and maybe one more with the second. That would create an interesting social dynamic, with height being used amongst women as some sort of seniority system. Not that this would be good, but I think that's what we'd see.
Now what would be weird is if humans had the same kind of social system where only the "queen" gets to breed.
Posted by: Inoculated Mind | March 23, 2007 5:10 PM
CCP: I made the mistake of summarizing years of research (by me and my colleagues) in a phrase.
The physical morphology is all in the head .... some would say my head, but I contend in the hominid (and rat) head. There seems to be a set of features that emerge when consumption of USO's is important, having to do mainly with the fact that USOs are digested in the mouth to a much greater degree than in the gut, as well as their toughness, etc.
Of course, the rodents are tiny so you need to use a magnifying glass....
Posted by: Greg Laden | March 23, 2007 5:11 PM
Oh, what I wouldn't give to have gained a couple of inches with each pregnancy! To actually be able to change lightbulbs without a ladder, buy groceries without climbing up the shelves. . .
Inoculated Mind, while tallness in women who've had multiple children might not be a mark of status, it sure would make it easier to pick out the quiverfull moms.
Posted by: Alison | March 23, 2007 7:18 PM
And they return to their normal size once the human female stops breastfeeding. But, it was fun while it lasted.
(Not that I am a male chauvinist sexist pig, or anything. Some of my best lovers had flat chests.)
Posted by: Mike Haubrich | March 23, 2007 8:44 PM
Uh, my wife was a C before she got pregnant. She grew to probably an E or an F while breastfeeding our daughter. She shrunk back to a D when she was done.
Reportedly my wife's mother had an A at most prior to her first pregnancy. I would guess around a D, now, but I'm not sure.
Posted by: Azkyroth | March 23, 2007 10:37 PM
Well, the main complaint my formerly breast feeding friends & sister say is that when the breasts shrink back after weaning they also lose firmness, and it can be a bummer in that it feels like part of your body suddenly aged.
Posted by: Sea Creature | March 24, 2007 11:30 AM