Common Problems in Rats

a ratA rat's lifespan is only 18-48 months so ageing changes and natural fatal conditions such as tumours are fairly common. Tumours are especially common for two reasons – many rats are descended from strains specially bred for the study of tumours and also because some tumours are viral in origin. Here we cover the more common conditions you should recognise so that you know when to take your rat to a veterinarian. Many people think it is not worth taking a pet rat to the vet but those with rats as pets or show animals can become very attached to them.


Itchy skins and scabbing due to mite infestations are common. They are relatively easy to treat but it must be remembered that many rats carry mites without signs and that the signs are due to lowered immunity – i.e. there is another problem! This may be due to stress, e.g. husbandry problems, change of owner/house, addition of new rats, etc, but can also be due to underlying disease especially internal tumours.

Mammary tumours

Cancer of the mammary glands is very common in rats. The masses are usually benign. However, they will often recur all along the mammary line from chin to groin. However, surgery is often relatively straightforward and removal of masses as they occur will often prolong the pet’s life. There also appears to be a hormonal aspect to these tumours so spaying female rats (especially before they reach puberty) may act as a preventative measure.

Respiratory Disease

Pneumonia and upper respiratory infections are common. They are frequently caused by viruses, bacteria and by Mycoplasma spp all of which may be carried by healthy rats. Disease therefore may be secondary to stress (e.g. mixing of rats, change of home), husbandry problems (especially where there may be irritant fumes) and underlying disease (especially tumours). Antibiotics will treat bacterial and mycoplasmal infections but not viral ones and, in all cases, the underlying factors must be addressed.

In many of these infections a red secretion may be seen from the eyes and nose. This is not blood but a pigment (porphyrin) secreted when the upper respiratory and conjunctival areas are inflamed. It may also be seen when rats are stressed or even when they are handled roughly.

This is only a small survey of the problems you may see in pet rats. Many diseases are related to poor husbandry, showing the importance in keeping your pet in the best possible conditions.

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