Domestic ferrets rarely live more than a decade, with their life expectancy being between five and 10 years. Some ferrets may live as long as 13 or 14 years, but the average lifespan of a ferret is closer to eight years
Ferrets are susceptible to a number of common diseases that can shorten their lifespan significantly. Adrenal disease is the most common chronic illness seen in ferrets, and it can be fatal if it causes enlargement of the prostate, leading to problems eliminating waste.
Insulinoma is the second most common chronic illness seen in ferrets. Small tumors form on the pancreas and overproduce insulin, causing the animal's blood sugar to drop drastically.
After the age of three, it is recommended that ferrets be monitored for these illnesses by running blood glucose tests and adrenal panels. Lymphoma and cardiomypathy are less common, but they are still leading causes of death. Human influenza can infect ferrets and potentially kill them if untreated.