Breeds with health problems

A breed is said to have health problems when the animal is restricted in natural behavior or suffers illnesses, discomfort or pain from a special characaristic that is bred.
Among mice actually only fancy mice are affected. But for them there are several suffering breeds known which are introduced in the following.

A fat Ay-mouse

Fat mice, the so-called Ay-mice possess a gene which makes them grow more and more fat - even if only fed a low fat diet. Additionally a low fat diet is difficult to realise when there are also slim mice in the same group.
The heavy weight causes damages on organs and joints. These mice have a higher risk for early death. In addition to that extremly fat mice are a kind of disabled. They have difficulties to climb or are even unable to do it.
The Ay-gene is linked to special fur colours. Usually red, orange and yellow-ish mice with black eyes have a high risk of getting extremly fat.
Not every mouse of these colours possesses the Ay-gene but most of them do. Occasionally you can find pathological adiposity on other colours.

Long hair mouse

Long hair mice have a longer coat that sometimes reaches the ground. Because the underfur is fair and a bit longer, its function of insulation doesn't work as effective as it would for short hair mice. That's why these mice tend to get cold sooner than normal. The vibrissae are often curved and the mice have a higher risk on getting several illnesses, especially skindiseases.
Long hair mice are supposed to be more sensitive of anaesthetics than short hair mice. Like curly mice they should be narcotized by gas not by injection.

Curly mouse

These mice, also called frizzie mice, have a short or long wavy or curly coat.
The coat usually is less compact than the one of ordinary fancy mice and they have a higher risk to fall ill or get parasites. The sense of touch is more or less limited depending on how curled/deformed the vibrissae are. You can find individuals that have only slightly wavy vibrissae, but you can also find poor little mice which vibrissae grown into their eyes and nose causing pain and inflammations. The intensitiy of this characteristic depends on the special gene causing curly hair.
Heavily bent eyelashes can irritate and hurt the eyelids or the cornea. That's why these mice often have inflamed eyes.
Curly mice are supposed to be more sensitive of anaesthetics than ordinary mice. Like long hair mice they should be narcotized by gas not by injection.

Hairless mice, also called skinny mice, skinnies oder sphinx mice, are mice without any hair on their body. There is also another form of these mice: Individuals with very few hair, called fuzzy or fuzzy hairless mice. The warming coat is missing and so are the vibrissae, too. This handicaps their sense of touch dramatically. That sense is important to mice in particular and that’s why hairless mice are truly disabled.
Furthermore these mice need more external warmth because they have no protecting coat. A normal, mouse-like life is impossible to them, even though they are born with the same needs as every fancy mouse with a coat.

Tailless mice, also called Manx mice, are supposed to be bred for people who dislike the sight of a mouse tail. But missing the tail the mouse misses a very important body part they usually use to balance, to climb and also to walk. For a mouse loosing its tail is the same as for a human loosing an arm. The mouse is limited very much in its movements and its natural behavior.
The mutation causing taillessnes can also cause some other problems: Serious deformations in the pelvis and the spine can occur and disable the victim to walk. Adhesion in the spine make the mice hopping instead of walking. Incontinence may also occur. Females are often sterile or have problems giving birth.

Dancing mice are very tiny, almost always black and white brindled mice with a noticable short tail. They are born with a brain damage. Damages of the pituitary gland cause dwarfism and other problems. Additionally the mice are nearly deaf because of serious damages of the inner ear. By these damages also the so-called „dancing“ is caused. The mice aren't able to walk straight forward, they „dance“ in circles. Sometimes they are running very fast for their own tail or round a dish or another item for hours. Climbing is also difficult to them because of their congenital damages. Some individuals aren't able to climb at all because they cannot distinguish above from below.
One further problem of the congenital damages is a weak immune system. That's why theses mice fall ill much sooner than ordinary fancy mice.
The degeneration is that serious that dancing mice are not able to breed with each other. Their children would be born dead.
Depending on the level of the damage some individuals aren't able to lead a normal social live in all aspects.
Usually these seriously damaged animals won't reach much more than an age of 6 months.

In the following you see a video I found on youtube. In the video you can see very well the typical black and white brindle, the dwarfism and also the physical constraint (the sloped head, problems with orientation, obessive random running in circles round an item or their own centre).

Source
www.rmca.org

Translation
Angelus Noctis