RatPalace.com - Pet Rat Care and Discussion

Mon Apr 21, 2003 11:26 am

All,

I believe I can see some of my females going through estrous cycles by noticing changes in the appearance of their genitals. However, I notice that several of my females always appear unreceptive, dry, and closed, despite living with males.

I have several questions:

- Do any of you all notice that your females are going into heat when you examine them?

- Have you ever found an 'always closed' female to have gotten pregnant? I know that females will remain closed once impregnated, I am trying to ascertain whether this condition will prevent these females from reproducing.

- Has anyone noticed any behaviour changes as a result of a female mouse coming into heat?

- If all of the males that a female is housed with are not sexually mature and/or sterile, will the females still come into heat? Ie does this attribute also prevent this male from producing the phermone that triggers estrous in the female?

Thanks.
K.

Mon Apr 21, 2003 2:07 pm

hey,

I will try to answer your questions tho, i don't have answers for them all.

I have never noticed my female mice going into heat and I don't think I have any always closed females so I can't answer the second question.

The only behavorial difference i noticed was my black female, Lily started to nip after she got pregnant.

Female mice go into heat every 3 to 4 days. No matter if they are in with males or not. Even when they are with sterile males.

Do you have your males and females together? Are you trying to mate them?

Fri Apr 25, 2003 5:21 am

Thanks for the info!

I have had two colonies of mice for several months. From reading information on the internet I should be able to tell the four stages of a female mouse's estrous cycle by looking at her genitalia. I have seen "gaping wet" ones on occasion. I know the mice actually only come into heat for several hours and therefore my chances of actually seeing it aren't all that great. ve never seen either of my girl Rats do it either! EVER!

I've also read about a phenomenon where female mice are sensitive to olfactory cues in male mouse urine and that stimulates them to come into heat. Female mice housed alone did not come into heat but after being exposed to male urine the cycle started within 72 hours. I believe this to be an accepted fact because it is mentioned in so many places and I think it's called the Lee-Boot effect. So I thought that perhaps my boys are not making the right smell for some reason?

Since I've had them for more than two months, and only a couple looked to be as young as 3-4 weeks of age when I got them (not that I'd know if they were too young) I am sure all of them are over sixty days old and should be sexually mature.

I am extremely cautious about poking around them and staring and pulling their limbs off and otherwise bothering them, and their houses are clean and full of toys so they are always doing things; I don't think the mice are under any kind of stress or emotional trauma. The boys don't even fight!

Anyway as I said there are two small colonies containing males and females and would like to have exactly one litter to keep through their natural lives. And I would have also expected more than one pregnancy by now! Unfortunately that was a sad ending as she did not survive labour Sad