>Has anyone seen a birth like this?
>
>My 10-month-old female gerbil normally gives birth to 3-5 offspring. She
has
>had several healthy litters. She delivered the previous litter of four June
>2, and mated shortly thereafter.
>
>She produced a peculiar litter of pups this morning. There were a total of
>eight, with four healthy pups and four pups whose development was clearly
>very incomplete. The incomplete pups appeared to have no external
>abnormalities other than their reduced size and "fetal" appearance. The
pups
>were produced in pairs of one healthy, one underdeveloped (and stillborn).
>The pairs were each delivered almost as one birth, with the live pup first.
>As far as I could tell, there appeared to be only one placenta per pair.
>
>Any ideas as to the explanation of this event?
Dipping into my experience with other animals.
You have a case of 'twinning'. Some internal or external cause
during very early division of the fetus, caused the original four
to divide and become identical twins. (usually within the first
eight to nine divisions) However, there seems to have been
some sort of developmental problem farther down the
gestation, and one of each twin stalled in development. And
that fetus died.
One placenta per pair, is further proof of the twinning.
Each of the underdeveloped twins died (not unusual at all)
probably from an abnormality that could be traced back to
the original division.
It happened close enough to delivery that the undeveloped one
of the pair had not been resorbed; and/or had not decayed such
as to cause the more advanced one's death by poisoning the
amniotic fluid or having things leak back through the shared
placenta.. Or causing a spontaneous early abort.
It is unusual, that you had four separate twin pairs. Usually only
one in a multiple birth will twin off....
It would have been great if you had taken pictures for posterity.
I know, it wasn't a thing that normally someone would think of
taking pictures of....and if you'd been closer, I would have loved
to have gained a sample of the leftover material (a placenta and
one fetus) for further examination. I assume the mother cleaned
up the detris?
One more question; what is the genes of the parents involved?
I am sincerely hoping that this litter thrives, and keep me
apprised of what colors you get....and breeding them back
might prove interesting.
Deb
Rebel's Rodent Ranch
