Rawhide is not suitable. The most common diseases of rats are respiratory illness and tumours. Respiratory illness is caused by an organism Mycoplasma pulmonis and should be treated with antibiotics. If your rat is making a wheezing noise seek veterinary advice immediately as this illness can kill quickly. Rats do occasionally have a sneeze and this is no cause for concern.
Tumours tend to be more common in older female rats.
These lumps may appear around the neck and under the stomach, in armpits or groin area. Many of these tumours can be removed by a veterinarian. Other tumours may occur in the brain, back and feet. Seek advice from a veterinarian. Rats who are ill or under stress may have a red stain around the eyes, nose and ears.