Diabetes is relatively common can affect both cats and dogs. There are two types of diabetes, diabetes mellitus and diabetes insipidus. The most common is diabetes mellitus which occurs when the pancreas does not produce enough insulin. Diabetes Insipidus is rare and affects how the body metabolises water. Excess drinking and urination are some classical signs of diabetes. Others include increased hunger, weight loss with a normal diet and in later stages lethargy and depression. Blood tests are required to diagnose the condition and many pets & owners manage very well with medication.