Hello everyone...got some questions about litters of pups...

[Mary Plummer]

Hope you're all having wonderful Saturdays!

My question comes from a fascinating article I just read in "American Scientist," called "Prenatal Hormone Exposure and *beep* Variation: Hormone Exposure in the Womb is Instrumental in Shaping the *beep* Anatomy, Physiology and Behavior of Mammals." The author did most of his work on mice, but draws broader conclusions, which really got me interested. He has demonstrated that in litters of mice, with both male and female fetuses, the female ones are affected by the testosterone produced by the male fetuses. Depending on how close the females are to the males in the uterus, they can end up behaving more like the male mice than like the typical female mice. I of course got to thinking about dogs, and was wondering whether anyone has observed this in pups. He also talks about how pregnant females subject to stress (like overcrowding, food shortage, etc ) produce testosterone, which then affects their litters. It really was a fascinating piece! He concluded it talking about twins in humans, and also human exposure to various "hormone mimics" in the environment, and how that can affect fetal development. So any insight you can share with me on how this all might apply to dog litters would be greatly appreciated!


Mary

[davet]

was determined byt the x and y chromosones..in alligators and some other reptiles the *beep* is determined by the temperature of the incubation....will have to wait for better minds than mine to figure out what the article is really saying...

[Mary Plummer]

...the actual *beep* of the animal as it was behavior. The female fetuses exposed to their male siblings' testosterone in the uterus were more likely to "act" like males than were others. What made me wonder a little was how much is it prenatal testosterone and how much of it is later learning from/with litter-mates. It was really interesting when it talked about when mothers are under stress, they actually produce more testosterone, which leads to more "masculine-acting" female offspring. So I was wondering whether or not this is observable in dog litters, too...if some females are more "male-acting" than others, or if this is even apparent in dogs.

[k9Karen]

I know there was a study of humans a while back that concluded that exposure to testoterone while in the womb was a major factor in the development of mathematic abilities. If I remember correctly, they monitored hormone levels of women when they were pregnant and then monitored their children as they grew. They concluded that the girls that were exposed to the highest levels of testosterone had the highest math abilities. I don't think they monitored aggessive tendencies though, and as an aside, I'm very good in math, but not aggressive at all. Assertive sometimes, and stubborn (ahem - I mean tenacious) when necessary, but definitely not aggressive.

Perhaps one of the vets can enlighten me, but wouldn't any testosterone produced by a male fetus be absorbed into the mother's blood stream before it could be passed to a nearby female fetus? Each pup has it's own umbilical cord and amniotic sac, so how could the testosterone pass directly from one pup to another? Osmosis? It doesn't follow from what I know about embryology (which, of course, was only one junior-level course in college 30 years ago, so expert I'm not).

[Traci]

Personally, I don't get the rationale of this 'study' and it sounds like a whole lot of money was wasted at the lab's expense.

As Karen notes, as each individual has their own sac, etc, I would argue if a male embryo could pass testosterone to a female embryo. After all, the gender is already developed, I don't see how anything that occurs in further development in the uterus could possibly affect traits, behavior. JMHO, but I think traits are developed through genes, and behavior is developed through environmental factors.

[davet]

even though each individual pup is in its own sac does not the blood each pup receives come from the same source and leave for restoration through the same source, ie the placenta.if the mother is poisoned are not all the pups poisoned ergo if each pup is sending it blood through the placenta filtered and reoxygenated then goes into the blood stream and if the testosterone etc were not compltly filtered by the mothers liver will it no be evenly distributed to the pups...sometimes i argue so logically that i forget where the hell i was going...

[Traci]

LOL, Davet! I actually understood where you were going!

And following that reasoning, if the pups are absorbing whatever from the mother, wouldn't that lead you to believe that everything trait/behavior wise would be female oriented? Or if testosterone were released, why doesn't the mother show those traits? Don't answer that, just a fleeting thought in my head

[davet]

answer as follows

beats the hell out of me !!!!!

[Traci]

Good answer, ROTFLMAO!

[momPaws]

I love these intellectual discussions...!