Or is it an baseless popular urban legend. A fact that 'Everybody' knows, just like 'Everybody' knew not so long ago that the world was definitely flat, and that holding flowers in front of one's nose was a sure-fire preventative against contracting the plague, and that if one was overly amorous with one's self, that one would go blind.
The topic of discussion here are plastic and metal hamster wheels where the design consists of two metal or plastic 'rings' joined to each other by metal or plastic cross-pieces or 'treads', which were spaced uniformly apart from one another.
I've long heard that these wheels are dangerous to the feet/legs/lives of small rodents such as hamsters, gerbils, mice, rats and really tiny Yorkshire Terriers.
The supposition is that rarely does a critter hit EVERY tread dead on, and that as a result their leg/foot/paw/tail/other dangling appendage might drop between the quickly moving bars and be trapped there and snapped by the motion of the wheel, and I assume the inertia of its mass traveling away from it.
I've had hamsters off and on for the last 20+ years. 20+ years ago, these were pretty much the only style of wheel available. I've had probably upwards of 80 hamsters (Including litters that after being weaned are allowed to mature in their own cage [containing one of these wheels] a bit more before going to new homes), and I've NEVER seen this happen.
Not only do I lack a personal first hand account, I've NEVER seen or heard of ANY other first or second hand accounts, or documented occurrences or research of this happening...
Despite this... Everybody KNOWS it to be God's Honest Truth.
I may be poorly informed. I may just have the common sense to question things before I spout them off to others.
Who's to say that this isn't just a malicious rumor being spread by the manufacturers of Habitrail voidless wheels, or the manufacturers of the Silent Spinner, Wodent Wheel, Comfort Wheel, etc.
After all... it was the tobacco industry that bribed the government into declaring Marijuana a dangerous and therefore illegal substance. Wasn't it? Everybody KNOWS it to be true. Follow the money trail.
I for one question it using common sense.
These wheels are relatively low-mass flywheels that when abruptly stopped with a hamster inside, usually swing back 10-15 degrees and then oscillate 2-3 times and come to a dead stop at the bottom of the arc. Hamsters are very low mass critters with a low center of gravity and no tendency to 'pitch forward and "wrench" or "break"' an appendage as a human might if a foot is trapped while moving briskly forward.
I really see this as possibly being a situation where someone developed a fear of something because on the surface it seems plausible, and horrifying if it happened, and never applied critical thinking (or facts) to test the validity and likelihood of just such an occurrence.
This person would of course be someone with a big heart (and a normal sized mind... doing this wouldn't make them 'stupid', just a little reactionary) who would then rush to share their concerns with other small pet fanciers. It would then expand to the world at large with alarming rapidity with the backing legitimacy of something that has absolutely no basis in fact or reason. This is how most urban legends begin and continue life.
Now.. with that in mind, I do have a warning for those who do keep rodents and might be inclined to purchase the following wheel from Wal-Mart, or PetCo where I've seen it sold... (By the way, I'm not one of those nutters who goes all out against PetCo. My local PetCos are wonderful, and safe. I've no doubt that there have been some rotten apples in the bunch, and perhaps even a reluctance on the part of corporate to investigate and clean house... but nothing justifies this idiot campaign against them.)
This I call "The Wal-Mart Wheel 0' Death which doth sever and rend thy hammy in twain."
Now... in all fairness, while I purchased the wheel at Wal-Mart, the image is linked directly off of PetCo's website.
In it's 'attached to cage' AutoBot/Transformer/Macross configuration, its perfectly safe... See
http://hamstercam.bramblethorne.org for such a configuration in use.
In it's unaltered (as shown) 'self supporting' AutoBot/T.... configuration its a veritable slice and dice and make julienne hamsters (I don't know if it juices or not) Wheel 'O Death!.
Imagine for a moment if you will... several hamster adolescents recklessly driving their wheel with speeding abandon to the sharp curve ahead in the road... Sealing their fate to be plunged into...!!!!... The chasm of despair that is caused by,
"The Wal-Mart Wheel O' Death".
They are all running that wheel in the same direction, hell bent for leather. If you've ever seen a hamster in its wheel, it does not actually have feet or legs, or actually in fact touch the spinning wheel. In fact it hovers about a quarter inch above the rotating surface, making marvelous use of the ground effect phenomenon, the Bernoulli's principle, and of course the famous vertical Coriolis effect which I've just made up.
Now.. Tragedy may strike if one hapless hammy somehow gets near the place where the crossbar support that runs along the bottom edge of the wheel meets the spinning edge of the wheel. This may happen for any one of a number of reasons. The first is... Hamsters are not especially bright. I've never known one to hold a PhD. The second, and more common is the fact that for every three hamsters running inside the wheel, there 3 more trying to get inside and being flung across the cage, and three more are running ON TOP of the wheel, or at least, trying to. Its a recipe for disaster.
The final component to this Ford Pinto like firetrap is the fact that the cross bar which forms half of the throat constriction/narrowing danger spot, is itself very flexible. This allows, with enough force, for a hamster to be push/pulled far enough into that throat and completely between the two opposing sides of the wheel edge and the crossbar, but not enough flexibility for the hamster to possibly make it through to the other side with minor or major damage. The strong plastic creates a viselike, scissor like pinch on the hamster, and prevents the hamster (if its still alive) from escaping it's clutches. One other thing to note is that the wheel has a lot of trapping friction due to its crenulated edge, and that for some BONEHEAD reason, the inside edge of the crossbar is sharpened to a fairly keen edge that is composed of LESS THAN 90 DEGREE angled sides, making it a fine chisel point.
Try running your finger through there to the other side.
When you've passed out from exhaustion after running around screaming about this devil device which is cutting your finger off and won't let you free yourself, someone with a kind heart can pull the two halves apart and free you and hopefully put a Band-Aid (tm) on your Boo (tm).
Our hamster however was not so lucky. Her ribcage was the part of her caught in-between the wheel and cross piece. Her ribcage was crushed and her heart, lungs, etc., were all forced down into her cavitas abdo'minis et pel'vis. Or in layman's terms, it crushed her and turned her into so much ground hamster.
I was so angry and upset when it happened that I shattered the devil thing against the far wall. My wife (the sensible one) prevented me from destroying the three others we had bought at the same time but had not yet 'installed'. This should give a clue about how long it took for this to happen. Two days. We had the thing in the bloody cage for TWO DAYS and it munched a beautiful little juvenile hamster.
Conclusion. But a Silent Spinner. Buy a Wodent, or comfort wheel. Maybe even buy one of the new mesh floored/tread metal wheels. But don't buy this thing if you intend to leave it in it's 'Stand Alone' configuration, unless you really hate your hammy. Whatever you buy however. Buy it for the right reasons and based on sound research. Don't buy or choose not to buy based on hype.
If you've gotten this far, then you'll probably also realize that you should 'not take my word for it'. There may be first hand accounts and research that the cross-treaded with voids between wheels are dangerous. There may be a gruesome memorial website showing pictures and the guilty wheels who did the damage out there with the words "Never Forget" in 96pt bold font at the top of the page. I've just never run across such. It doesn't mean that such isn't out there.