Heart failure is the leading cause of death in Rat Terriers, though it typically doesn’t develop until old age. This breed lives 12 to 18 years on average, making them one of the longer-lived dog breeds. Most Rat Terriers that receive routine veterinary care will enjoy the upper end of that range, but several health conditions can shorten their lives or lead to difficult quality-of-life decisions.
Heart Disease
Cardiac disease tops the list of what ultimately kills most Rat Terriers. The condition usually shows up late in life as the heart muscle weakens or the valves degrade, making it harder for the heart to pump blood efficiently. Early signs include coughing (especially at night or after exercise), tiring more quickly on walks, and labored breathing while resting. These symptoms can creep in gradually, so they’re easy to dismiss as normal aging.
Because heart disease is so prevalent in the breed, the national breed club recommends a cardiac exam as one of the core health screenings for Rat Terriers. If you’re buying from a breeder, ask for documentation of this test on both parents. For dogs you already own, a vet can listen for murmurs during routine checkups and order an echocardiogram if anything sounds off. Caught early, heart disease can often be managed with medication for months or even years.
Dental Disease and Organ Damage
Small breeds like Rat Terriers are especially prone to dental problems, and this matters more than most owners realize. Plaque and tartar buildup allows bacteria to spread beneath the gumline, causing painful infections and tooth loss. But the real danger is what happens next: those bacteria can enter the bloodstream and travel to the heart, kidneys, and liver. Once there, they cause infections and chronic inflammation that damage these organs over time.
Heart infections (endocarditis), kidney disease, and liver problems can all trace back to untreated dental disease. In a breed already predisposed to heart failure, poor dental health essentially accelerates the timeline. Regular dental cleanings and daily tooth brushing are two of the most impactful things you can do to extend a Rat Terrier’s life.
Seizure Disorders
Rat Terriers, like many purebred dogs, have a higher risk of idiopathic epilepsy, a seizure disorder with no identifiable underlying cause. Epilepsy itself isn’t always fatal, but it can lead to euthanasia when seizures become frequent or severe enough to destroy a dog’s quality of life. The biggest risk factors for that outcome are seizures that start at a young age, a high frequency of episodes early on, poor response to medication, and episodes of status epilepticus, which are seizures lasting longer than five minutes.
Most epileptic dogs have their first seizure between one and five years of age. If your Rat Terrier has a seizure, a vet will typically run blood work and imaging to rule out other causes before diagnosing epilepsy. Many dogs respond well to anti-seizure medication and live full lives, but ongoing monitoring and dose adjustments are part of the long-term picture.
Joint and Mobility Problems
While joint conditions don’t directly kill Rat Terriers, they’re a common reason owners face end-of-life decisions for aging dogs. The breed club recommends screening for both patellar luxation (a kneecap that slips out of place) and hip dysplasia. Patellar luxation is particularly common in small terrier breeds and ranges from mild, occasional slipping to a permanently dislocated kneecap that requires surgery.
Over years, untreated joint problems lead to arthritis, chronic pain, and loss of mobility. When a dog can no longer walk comfortably, get up from lying down, or go outside to relieve itself, owners and veterinarians often discuss euthanasia as a humane option. Keeping your Rat Terrier at a healthy weight throughout life is one of the simplest ways to protect their joints and delay these conversations.
Eye Conditions
Primary lens luxation is a genetic condition the breed club specifically tests for. It happens when the fibers holding the lens in place break down, allowing the lens to shift inside the eye. Left untreated, it causes glaucoma and intense pain, and can lead to blindness. A DNA test can identify carriers before breeding, so this is another screening worth asking a breeder about. Dogs diagnosed early can often be treated surgically before permanent damage occurs.
What Helps Them Live Longest
Rat Terriers are a robust, athletic breed with a genetic advantage when it comes to longevity. The 12-to-18-year lifespan range is wide, and where your dog falls on that spectrum depends heavily on preventive care. Annual cardiac exams become increasingly important after age seven or eight. Dental cleanings, even if they require anesthesia, pay dividends in organ health over the long run. Maintaining a lean body weight protects joints and reduces strain on the heart.
If you’re choosing a puppy, look for breeders who complete all four recommended health tests: patella evaluation, hip evaluation, cardiac exam, and the DNA test for primary lens luxation. These screenings don’t guarantee a healthy dog, but they significantly reduce the odds of inheriting the conditions most likely to cut a Rat Terrier’s life short.