Experiences with a runt: UPDATE

[michaeljack]

Rather than extend the original thread ("First experience with a runt: any thoughts?"), which provides background and photos of the runt's progression, I've created this. In addition, my member photo shows the original used in the first thread. 

Runt (that's his name) has grown up and is about 3/4 the size of a normal gerbil. I chose a female (Runt's Mate...that's her name) who, too, is a bit smaller than my general population. Also, I wanted her color since it represents one of the more occurring colors in Runt's family line; she resembles the color of Runt's grandfather, who incidentally (and ironically) is a larger-than-typical gerbil. I also chose her size in the event mating may later occur: 1, easier mating and 2, curiosity to see if any progeny would be smaller than normal. 

These photos are the latest as of July 31. I wanted to show that Runt's size is no longer a strong contrast but that his growth looks good. We babied him extensively and that could be a factor in his successful survival. He is still unusually sweet, and we can feel his slighter size when handled. The pair has mated and produced five babies. 


imgur.com/pm0tPAk

imgur.com/cYB4ouX

imgur.com/38dQjjt

Markpd
betty
tanzanyte
Shooting Star

[yeti218]

This is lovely, I'm so glad hes doing well.

[betty]

If he is a runt in the truest (is that a word?) sense - then it shouldn't be heritable as he wasn't genetically meant to be smaller - he just had bad luck in the womb. He would also potentially have some other biological issues as a result of that poor growth/nutritional input.

However, if the female developed as a smaller gerbil without having been a noticably smaller pup - then there is the possiblity that she could pass on some of that trait to her young in the right circumstances. Just like you can breed larger gerbils by always selecting for the larger adult in your breeder clans - you can successfully breed smaller from the smaller ones.

I had great success with a smaller-than-average line - with noticable size reduction in just a few generations.

[michaeljack]

Aug 5, 2021 10:18:52 GMT -8 betty said:

If he is a runt...

Thanks for responding, betty!
He's a genetic mystery. I purposefully attached him to his sister to see what might happen in the progeny. I, too, have a few  of what appear to be smaller than usual, but Runt isn't related to them. I do have an exceptionally small black/white female ("Tiny") who, at 5 months, is less than half "normal" size. Depending on Runt's current babies' development, I may try breeding him to the new female. 

Meanwhile, with respect to your information about creating smaller/larger gerbils, it's notable that Runt's mother (the biter) is actually larger than normal as is her father (extremely docile like Grandson Runt). None of her or his subsequent progeny have shown the larger size trait.

[betty]

Are you weighing them as pups too as smaller gerbils are smaller pups too - I created some interesting data lines when I was working on my line. It isn't in a format that is easily shareable - but if you have the pups wegiths atvarious days I can compare them to my lines?

And yes, genes can work in very strange ways sometimes - I am baffled as to how many records of everything it took early breeders of anything to figure out all the complexities!

[Markpd]

Thanks for the update Michael, sorry for the late reply, somehow I missed the notification!
Great that he's turned out so well, and keeping fingers crossed for some cute little pups