The #1 Killer of Cats Might Surprise You


It’s estimated that over 2.2 million cats died in the United States in 2016 alone. With mortality rates this high, identifying the leading causes of death is crucial for keeping our feline friends healthy and alive for as long as possible.

The goal of this article is to uncover the #1 cause of death for domestic cats by reviewing statistics and research on the most common ailments that claim cats’ lives.

Old Age

The natural lifespan for domestic cats is typically 10-15 years on average, though some cats have been known to live well into their 20s. As cats get older, they become more susceptible to health issues like kidney disease, thyroid disease, cancer, arthritis, cognitive dysfunction, vision and hearing loss.

Senior cats require more frequent veterinary checkups to monitor their health. Bloodwork and urinalysis can check kidney values and screen for issues like hyperthyroidism. X-rays and ultrasound imaging can evaluate organs for disease. Dental exams help catch painful mouth infections. Monitoring weight is important, as obesity worsens joint pain and other problems.

Providing excellent nutrition and limiting stress help senior cats stay healthier in their golden years. Keeping their minds active with play and affection also improves cognition. With dedicated care from pet owners, cats can continue enjoying life even as seniors.


Cancer is a leading cause of death in cats, responsible for approximately 32% of deaths in cats over ten years old. The most common cancers seen in cats include lymphoma, squamous cell carcinoma, mammary gland tumors, mast cell tumors, and fibrosarcomas. Lymphoma accounts for up to one third of all feline cancers. According to research, 53-85% of feline tumor cases are malignant cancers. While cancer can be difficult to treat if not caught early, modern veterinary medicine offers cat owners hope through surgery, chemotherapy, radiation therapy, and other treatment options.

Heart Disease

Heart disease is one of the most common causes of death for cats. According to a study, cats with current or past cat ownership had a lower risk of fatal cardiovascular disease compared to non-cat owners. Heart disease accounts for around 15-20% of deaths in cats.

There are several types of heart disease that affect cats. Hypertrophic cardiomyopathy (HCM) is one of the most common, affecting around 15% of cats. HCM causes thickening of the heart muscle, which can lead to blood clots, heart failure, and sudden death. Another type is dilated cardiomyopathy, where the heart becomes enlarged and weakened. Other less common types include restrictive cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and unclassified cardiomyopathy.

Symptoms of heart disease in cats can include lethargy, decreased appetite, trouble breathing, coughing, fainting, and sudden hindlimb paralysis. However, cats often don’t show obvious symptoms until the condition has progressed. Regular vet checkups to monitor heart health are important for early detection and management of heart disease in cats.

Kidney Disease

Kidney failure is very common in older cats. According to a 2014 study, the prevalence of chronic kidney disease (CKD) in cats over 10 years old is 30-40%. As cats age, their kidneys gradually lose function and are less able to filter waste products from the blood. Eventually, this leads to a buildup of toxins in the body.

Symptoms of kidney disease include increased thirst, increased urination, weight loss, poor appetite, vomiting, and bad breath. In the later stages, ulcers in the mouth may develop as well as anemia, weakness, and seizures. Treatment focuses on reducing the workload of the kidneys with a low protein diet, replacing lost fluids, controlling blood pressure, and treating anemia. Medications can help control vomiting and encourage appetite. However, kidney disease is a progressive disease, and most cats will eventually succumb to kidney failure.

Kidney transplants and dialysis are possible but uncommon treatment options due to the invasiveness of the procedures and stress on the cat. Euthanasia may be elected once the cat has poor quality of life from the symptoms of kidney failure.


Cats are prone to infections if not vaccinated properly. Some of the most common infectious diseases in cats include:

Feline panleukopenia virus (FPV) – Also known as feline distemper, this highly contagious viral disease attacks the gastrointestinal tract and bone marrow of cats. It can be fatal if left untreated. Vaccination is key for prevention (Source).

Feline leukemia virus (FeLV) – A retrovirus that suppresses the cat’s immune system, making them prone to secondary infections. It spreads through saliva and nasal secretions. Vaccination can prevent infection (Source).

Feline immunodeficiency virus (FIV) – Similar to HIV in humans, FIV attacks the immune system leaving cats vulnerable to opportunistic infections. It spreads through bite wounds and is incurable. Vaccination provides some protection (Source).


Trauma from accidents or falls is a major cause of death in cats. According to a 2021 study, trauma-related mortality rates of 9-27% have been reported in cats (Distribution of mortality patterns in cats with naturally occurring disease). Being hit by cars accounts for a significant portion of trauma in cats. One study found that blunt force trauma, which includes being hit by cars, accounted for 80% of trauma cases and had a 80% survival rate (Gregory, 2023). Reducing the risk of accidents, falls, and trauma can help prevent premature death in cats.


Cats are curious creatures by nature and will often ingest substances that can be toxic or poisonous to them. According to a retrospective study, poisoning accounted for approximately 13.6% of feline deaths [1]. Some of the most common sources of poisoning in cats include:

  • Pesticides and rodenticides – These chemicals are designed to kill pests but can be very dangerous if ingested by cats. Rat poison containing warfarin is a frequent cause of toxicity [2].
  • Household cleaners – Cleaning products like bleach, detergent pods, and toilet bowl cleaner can be toxic. Cats may walk through spilled products and ingest them when grooming [3].
  • Plants – Many common houseplants like lilies, azaleas, and rhododendrons are poisonous to cats if ingested.
  • Prescription medications – Opioids, antidepressants, and heart medications can cause poisoning if cats access and ingest them.
  • Automotive chemicals – Antifreeze has a sweet taste but contains ethylene glycol, which is extremely toxic to cats.

Due to their curious nature, owners must be vigilant about properly storing potentially dangerous substances in the home.



Obesity is a common condition in domestic cats and can lead to significant health problems. According to VCA Animal Hospitals, obesity reduces a cat’s life expectancy. Research shows that obese cats from 8-12 years old have a 2.8 times higher mortality rate compared to cats at a healthy weight.

Keeping your cat at a healthy weight is important. The Association for Pet Obesity Prevention recommends weighing your cat regularly and adjusting food portions or diet as needed. Provide exercise opportunities with play time and cat toys. Swap treats for healthy alternatives like chunks of cooked chicken or fish. Getting an overweight cat to lose weight requires patience and consistency.


To recap, the most common causes of death in cats are old age, cancer, heart disease, kidney disease, infections, trauma, poisoning, and obesity. Each of these can lead to illness or injury that results in a cat’s premature passing. However, old age is the #1 cause of cat fatalities overall. As cats grow older, their bodies naturally decline and they become more susceptible to disease and organ failure.

For cat owners, the takeaway is to cherish every moment with your feline friend. Provide them with proper veterinary care, a healthy diet, exercise and enrichment to maximize their longevity. But also understand that aging and eventual death are inevitable. Focus on your cat’s quality of life as they enter their senior years and make their comfort a priority. With love and care, you can ensure your cat enjoys their twilight years to the fullest.

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