A short mouse story-
I once owned 23 (or was it 26) Fancy Mice.
I started with two, but was stupid that day (well, a lot but we'll just stick to this incidence for now) and forgot all about checking for balls, even though I had hamsters as a kid and as an adult. And rats. Pet rats.
So I bought the little black mouse who was hiding on the water bottle, and sibling.
Little black mouse was already pregnant when I got her, but not showing. Her sibling had a penis anyway and tried to help.
Black mouse was apparently a fertile Myrtle and had 13 babies, all of whom survived.
She was an excellent mother and she also became my best buddy. Who wouldn't need an outlet raising that kind of multiple birth?
At least twice a day during my many visits to the mouse-errarium she would climb up to hang on the mesh lid and crawl back and forth, or stand with her nose poking out until I took her out and let her crawl on me. Sometimes I tried to put her back too soon and she would race the other way back up my arm.
When the babies got to a certain age- the age when they started to practice nookie like a couple of awkward thirteen year olds in the basement. It was time to separate.
Did you know little boy mice can hide their balls? I mean really hide. Or maybe it's that some just descend later than others. After all, people have late bloomers.
I know about the differing distance between urethra and anus in male versus female, and differently shaped abdomens, but try to figure that out with bad eyes and a hellbent 1/3-inch worm shaped tube of squirm.
Picture a giant, furry Tylenol with big ears.
I learned to gently push on the lower abdomen and look for bulges and that helped loads, but inevitably down the road I'd see somemouse previously female humping or chasing somemouse else and darnit if those little boy nuggets didn't suck right back in as soon as I went after the pertpetrator. Not always soon enough.
Some litters didn't make it at all. Some mice were horrible mothers. One litter had been decimated down to two babies and I finally turned them over to the again newly delivered original Momma who adopted them and raised them with her own.
At final count I had 23 mice and possibly ten cages. All the females cohabitated, and each male had his own domicile.
My two favorites were Mommma, and Scruffy. Scruffy was missing patches of fur from the skin rash that broke out among the males while they were still young enough to share a cage- a skin rash I hand treated each day with peroxide and cortaid on q-tips. Scruffy's tail was bent at the distal end from the day he tried to climb back onto me and I accidentally dropped the lid. His ears were incomplete from sibling squabbles before the separation. Scruffy was gentle and also loved to come out and sit in my hand. He would often sleep (in his own, private cage) on top of his bullet shaped unclimbable water bottle with one hind foot wrapped around the wire hanger. Scruffy outlived almost every one.