can size of running wheel be harmful ?

[jd]

can a wheel cause spinal injuries when it's too small ?

A disease/injury called wheel tail (curved upwards) or scorpion tail seems to be the result of (excessive use of / too small) wheels, causing damaged vertebrates !
Others say this disease is genetically present if it occurs.

Because I've read different things and didn't get search results easily here, please leave your comment.


On average my animals are small size gerbils (of which 2 of them are bigger ones and 3 are smaller ones) but they all love to use both big and small wheels.
When I see how excited they adore running in it, extensive use bothers me - if wheel size could be harmfull indeed.

The two 12-inch (30 cm)  wheels I have can only be used outside the cages (or with open lid).
The two 8-inch (20 cm) approx. wheels offer permanent access, hung in some of their cages.

-> are those 8" too small and dangerous ?

[betty]

I think it is more of a repetative issue really. Not a simple yes or no thing - although many people say the diameter should be 2 to 2.5 times the length of the adult animal running in it as a mimimum.

Just like borrowing shoes that are too small for you - or stooping for low beams when visiting a historic house - if you do something that creates an unnatural body shape just the once or every so often - it has no lasting effects.

Whereas if you do something more regularly or more obsessively then you can create yourself a strange pose - and this could lead to all sorts of structural anomolies - some not so bad and some that could become bad.

Now, if you wanted to go see historic houses - would you go see them even if you always had to stoop? This is the issue with small wheels. If - as you say above - your gerbils love wheels and only have access to the smaller one in their enclosure - then they are going to use it - regardless of if they have to change the way they run to do so comfortably (imagine how you run when in the open and how you would run if underneath low hanging branches).

So, if you can film them in slow-mo running in the smaller wheel it can really help to see if they are holding themselves differently to how they run in the larger wheel. If you think they are having to change anything for the smaller one - then perhaps it IS too small to use all the time. It is difficult when - like with you - the larger wheel doesn't fit in their current enclosure - but if they are always running on the wheel either way - then would running strangely be worse for them than not running in a wheel at all?

Overall, running obsessively in the 8" wheels 'could' cause medium to large adult gerbils muscular issues while holding up their head and tail (which can be seen in a change in shape to the tail over time as the muscles and tendons take on a new shape/length) and is best avoided where possible. However, if you don't have the option of a larger enclosure to fit the larger wheel - then the choice is down to how you feel yourself about this.

[LilyandDaisy]

I've also heard that wheel tail is probably more of a muscular issue than a bone one. Gerbils hold their tail above the ground when they run, and that includes when running on a wheel. Lots of time spent running on a wheel might cause the muscles to take on a new shape, but that isn't necessarily harmful.

My gerbil Daisy uses an 11" wheel a bit and I have noticed her tail tends to curve up at the end slightly when she's walking. I think it's a muscular thing rather than anything more structural, because when she's sitting still and her tail is relaxed, it looks normal. It's just when she's walking and her tail muscles are flexed. Her sister who never used a wheel had a completely straight tail. But I believe it's a purely cosmetic thing as I see no evidence of it causing her any discomfort or difficulties.

Ideally I would want a wheel big enough that a gerbil doesn't have to curve their tail at all but that's very hard to make space for (and very expensive). Personally, where I draw the line of a wheel that's definitely too small is when the gerbil's tail is forced directly upwards or their head is forced upwards and their neck bent (like this) as I think, like when you hold your neck in a strange position for a long time, it's likely to be uncomfortable. I think as long as the gerbil's head and body are horizontal and the tail is held straight behind them (even if it's curved slightly towards the end), it's probably ok. This video shows Daisy (and Tilly, but she's a tiny pup here) running on an 11" wheel for you to compare.

In practice I don't use anything smaller than 11" for gerbils.

[Markpd]

When this subject came up a while ago I did some hunting around youtube to try to find videos of gerbils running in rooms, or in the wild.

I did find one video of a gerbil running in a large room, and even then it seemed to be lifting it's tail a little (makes sense as otherwise it would hit the ground). It was somewhat hard to see though as the video wasn't very great quality though.

Perhaps there's a better one now? (I'm going to see if I can find one, when I have time!).