Size Difference Among Brothers?

[smilez_n_hugs]

This seems like a strange observation to me but since this is the second time I have noticed it I thought I would post to see if anyone has noticed this as well.

As some of you may know about a year and a half ago I adopted 3 baby boys from Lindy (lj) when she took in Ginny (a pregnant girl). They turned out to be big boys but I thought nothing of it because all 3 brothers are about the same size. But then maybe 8 months ago I had the pleasure of meeting some of my boys brothers that Lindy still has and I was amazed at the size difference. Her boys were normal sized boys while mine are huge (and to my knowledge all are unaltered).

A bit ago I was able to take in 2 of the boys from the TAS and Chelle took in 2 as well. In the past month and a half we have noticed that my boys, who are living in a CN with 5 other adult males have grown much faster than the 2 she took in who are living in a Martins R-680 with one other boy around their age. And it's not only the size difference we have noticed....we have also realized that my boys have already started getting buck grease and have larger testicles than Chelle's boys.

As of right now my thoughts are that this is an environmental adaptation to the boys being exposed to full grown adult males so their body adapts by having them grow faster and larger.

Has anyone else noticed any similar cases?

We might have the chance to try a 3rd case depending on where the Rocky Horror babies end up going.

 

[victoria]

I have noticed the same thing - rats will grow to their environment. Anytime I have upgraded cages or have adopted rats hat lived in smaller cages, regardless of their age, they grew. I don't mean only gain weight, but actually get bigger. Much bigger. (Oreo's the only exemption, she has barely grown although her sister who was the same size when I adopted them has gotten much bigger.)

I have also noticed that my rats all put on weight/get bigger after being introduced to new buddies. I think this is because they are all competing to be in charge, and size helps a lot in that endeavour.

The other thing I have noticed is that the amount out time can affect their size as well, I think this is related to the environment size. I let my rats out for almost 2 hours a day now, and they have not stopped growing even though they are all around two. (I have 6 rats in a double CN - 5 females and a male.)

There are other things I'm sure that play a role in their size - genetics, nutrition, personality to name some, but I very much believe that the size of a rat's environment plays a big role as well.

 

[jorats]

I have not noticed this. I have a family of 5 boys from the same litter. 3 became bigger rats while 2 stayed fairly small. All lived in the same cage with the same buddies, same food and same everything.
I'm pretty sure I read somewhere that rats stop growing at about 7 months to 12 months of age but can still become larger as we do, which is definitely dependent on food and exercise. We would have to start measuring the length of the rats at several stages in life in order to gauge if they are indeed "growing" or simply getting larger.

 

[smilez_n_hugs]

I have not noticed this. I have a family of 5 boys from the same litter. 3 became bigger rats while 2 stayed fairly small. All lived in the same cage with the same buddies, same food and same everything.
I'm pretty sure I read somewhere that rats stop growing at about 7 months to 12 months of age but can still become larger as we do, which is definitely dependent on food and exercise. We would have to start measuring the length of the rats at several stages in life in order to gauge if they are indeed "growing" or simply getting larger.

My case has nothing to do with them continuing to grow as I have gotten them as babies. Mine just seem to grow faster and larger and develop their testicles and buck grease faster. My guess is that its their hormones responding to the fact that they are living with full grown males in turn making them grow faster/larger so they can compete for dominance.

 

[jorats]

My case has nothing to do with them continuing to grow as I have gotten them as babies. Mine just seem to grow faster and larger and develop their testicles and buck grease faster. My guess is that its their hormones responding to the fact that they are living with full grown males in turn making them grow faster/larger so they can compete for dominance.

Oh, I totally understand now... yes, I would say there are factors that could cause the boys to mature faster like females in the room or living with older males and even certain stresses like for my 3 pews, the big move from NB to Ontario did it.