[Jack Garcia]

Have any of you found that some of your show mice have humps in the spine? I have found that in some of my mice (all PE-varieties), they tend to have humps on their back while resting. Some are much more noticeable than others. Is this a consequence of breeding for the long, racy shape called for in the standards? What seems to happen is that the arch required by the standard is "concentrated" and replaced by a big hump near the front of the mouse, while resting.

Health, temperament, and breeding all seem to be unaffected.

I have noticed that the mice with the hump always have very long tails (around an inch longer than their body, at least) and also always have moderate tail sets. I know that the tail and the spine are the same anatomical feature, so I wonder if and how it's related and inherited. I wonder if it may be caused by a single allele that does not affect coat color (mode of inheritance I do not know), or if perhaps it might be an accumulation of modifiers that have stuck together because many show mice are so heavily inbred?

Here are a few examples of what I'm talking about, from past and present mice that I've bred and other people have bred, but I've photographed:

I know it occurs in Europe as well, as some of my recent imports have this going on.

What are your thoughts?

 

[SarahY]

Mine do that too, it gets more noticeable as they age though. My mice look fine under about 14 weeks.

I don't know for sure but it seems likely it's a result of breeding for a longer body and tail.

Sarah xxx