Cats vs Dogs. The Great Pet Health Debate


The debate over whether cats or dogs are healthier has been going on for ages. Both species have unique anatomical, physiological, and behavioral attributes that affect their health. While challenging to definitively declare one species “healthier” than the other, a responsible pet owner can take steps to maximize their pet’s well-being. This article will compare key aspects of feline and canine health, examining their dietary needs, common diseases, parasites, lifespan, preventative care and more. The goal is to better understand the health considerations for each species. Cats and dogs both have unique health needs and risks. While challenging to declare one species healthier than the other, a responsible pet owner can maximize their pet’s health.

Anatomy and Physiology

There are some key anatomical and physiological differences between cats and dogs that can impact their health. Dogs have a more complex respiratory system and larger lung capacity than cats, but cats have a larger liver relative to their body size which aids metabolic function (WSU Veterinary Teaching Hospital).

Cats also have a more concentrated urine than dogs due to differences in kidney function, and their heart anatomy includes some unique adaptations like the papillary muscle that allow them to pump more efficiently at fast heart rates (Bothell Pet Hospital). Dogs have a more complex digestive system with a longer small intestine which aids food absorption.

Skeletally, dogs have more vertebrae and appendicular bones which gives them more flexibility and mobility. Cats have more bones in their thoracic limbs giving them greater jumping and climbing abilities. Overall, the anatomical differences between dogs and cats reflect their historic function as predators versus scavengers.

Dietary Needs

Cats and dogs have very different dietary requirements due to differences in their digestive systems and nutritional needs. Cats are obligate carnivores, meaning they require certain nutrients found only in animal flesh, whereas dogs are omnivores and can meet their nutritional needs with a combination of plant and animal sources (1).

Some key differences in their nutritional needs include:

  • Cats require a much higher amount of protein in their diet, as they lack the ability to synthesize certain essential amino acids like taurine (2).
  • Cats also need more fat and fat-soluble vitamins like vitamin A and D due to their carnivorous nature.
  • Dogs can adapt to a wider variety of carbohydrate sources than cats, who have a limited ability to digest plant material and require very little carbohydrates in their diet.
  • Cats require more phosphorous and magnesium in their diets compared to dogs.
  • Both cats and dogs require balanced amounts of calcium, but calcium needs differ between puppies/kittens and adult pets.

Due to these differences, cat and dog foods are formulated to meet the specific nutritional requirements of each species. Feeding the wrong diet can lead to nutrient deficiencies and health issues over time. It’s important pet owners understand their pet’s unique nutritional needs.

Common Health Issues

There are some recurring health issues that are common among both dogs and cats. However, there are also some key differences in the common conditions affecting each species.

For cats, the most prevalent health issues include:

  • Kidney disease – This occurs when the kidneys can no longer efficiently remove waste products from the blood or perform their regulatory functions. Kidney disease is estimated to affect up to 30% of older cats.
  • Hyperthyroidism – This is characterized by an overactive thyroid gland. It’s relatively rare in dogs but affects many older cats. The excessive thyroid hormone production can lead to unintended weight loss and other metabolic issues in cats.
  • Dental disease – Periodontal disease is very prevalent in cats, with estimates ranging from 50-90% for having some degree of dental disease. Poor dental care can also contribute to issues like tooth decay and oral infections.

In dogs, some of the most common health problems are:

  • Obesity – Carrying excess body fat puts dogs at risk for diabetes, heart disease, arthritis, breathing issues, and more. Over 50% of dogs in the U.S. are estimated to be overweight or obese.
  • Arthritis – Joint inflammation and deterioration affects many dogs, especially large breeds and senior dogs. Arthritis can significantly impact mobility and quality of life.
  • Dental disease – Like cats, poor dental health is widespread in dogs. Tartar buildup, gum disease, and tooth decay are common.
  • Heart disease – Dogs can develop heart issues like valve degeneration, enlarged heart, arrhythmias, and heart failure. Certain breeds like Cavalier King Charles Spaniels are prone to heart conditions.

With proper nutrition, regular veterinary care, dental hygiene, and lifestyle management dogs and cats can live happily while minimizing many common health risks.

Infectious Diseases

Cats and dogs are susceptible to some shared infectious diseases, but they also have unique infectious diseases. For cats, some of the most concerning infectious diseases are feline immunodeficiency virus (FIV), feline leukemia virus (FeLV), and feline infectious peritonitis (FIP) [1]. FIV is similar to HIV in humans and attacks the immune system, making cats more prone to other infections. FeLV suppresses the bone marrow and weakens the immune system. FIP is caused by mutation of a harmless coronavirus into a fatal form that causes systemic inflammation. For dogs, some of the most common and serious infectious diseases are canine parvovirus, kennel cough, and leptospirosis. Canine parvovirus is a highly contagious viral illness that causes severe diarrhea and vomiting. Kennel cough is an upper respiratory infection that causes persistent coughing. Leptospirosis is a bacterial disease that can lead to kidney and liver failure [2].


Cats and dogs are both susceptible to parasites like fleas, ticks, and intestinal worms if not properly treated and prevented.[1] Fleas and ticks are common external parasites that live on the skin and can cause irritation, infections, and transmit other diseases. Intestinal worms like roundworms, hookworms, tapeworms, and whipworms live in the digestive system and can cause vomiting, diarrhea, and malnutrition.[2]

Regular use of flea and tick prevention medications like Frontline, Advantix, Nexgard, or Seresto collars can eliminate external parasites. Treatment for internal parasites involves dewormers like pyrantel pamoate, praziquantel, or milbemycin oxime. Kittens and puppies need to be routinely dewormed. Adults should receive fecal tests and deworming if parasites are found.[3] Keeping the environment clean and avoiding exposure to parasite eggs or larvae can also help reduce transmission.

Life Expectancy

When it comes to average lifespan, cats tend to outlive dogs by a small margin. According to research, the average lifespan for cats ranges from 12-15 years, whereas dogs typically live between 10-13 years on average (Source). However, there are many factors that impact lifespan for both species.

One study analyzing data from over 30,000 cats and dogs found that the median lifespan was 14 years for cats and 11.8 years for dogs (Source). However, lifespan varies significantly based on breed – larger breeds tend to have shorter lifespans than smaller breeds for dogs. There are also differences based on sex, with female cats and dogs often living slightly longer than males on average.

Other factors like nutrition, exercise, veterinary care, and exposure to infectious diseases also play an important role in determining lifespan. With proper preventative care and a healthy lifestyle, many cats and dogs can live to 15 years or even longer. But on the whole, cats appear to be programmed for slightly longer average lifespans compared to dogs.

Behavioral Health

Both cats and dogs can develop behavioral health issues that impact their overall wellbeing. However, some common issues differ between the two species.

Cats may experience stress-related behavioral issues like inappropriate urination outside of the litter box. This can be triggered by changes in their environment, interactions with other pets, or anxiety. According to a study by the ASPCA, among cats surrendered to shelters, house soiling is the most commonly reported behavior problem.

Dogs frequently suffer from separation anxiety when left alone, which can lead to destructive behaviors like chewing, barking, or elimination. Certain breeds like Labrador Retrievers and German Shepherds are prone to separation anxiety. Aggression is another common behavioral problem in some dog breeds if not properly socialized and trained.

While behavioral issues can arise in both species, identifying and addressing the underlying causes with proper training, socialization, and veterinary support can help improve their welfare.

Preventative Care

Preventative care is crucial for cats and dogs to maintain optimal health and prevent disease. This includes regular veterinary visits, vaccinations, parasite prevention, and wellness exams. According to the ICW Veterinary Hospital, annual exams allow vets to detect problems early and start treatment right away. Cats and dogs require core vaccines to protect against dangerous diseases like rabies, parvovirus, and distemper. These vaccines stimulate the immune system to create antibodies and prevent future infection. Both species also need routine parasite prevention to avoid infestations of fleas, ticks, heartworms and intestinal worms. Products like topical flea/tick medication and heartworm prevention medicines safeguard pets against parasitic diseases that can damage organs or even be fatal if left untreated. With proper preventative care, cats and dogs are more likely to enjoy longer, illness-free lives. The American Animal Hospital Association recommends twice-yearly veterinary visits for adult dogs and annual exams for adult cats.


In summary, there are both similarities and differences when it comes to the health of cats versus dogs. Both require proper nutrition, exercise, veterinary care and responsible ownership to live long, healthy lives. However, cats and dogs have some key anatomical, physiological and behavioral differences that predispose them to certain health conditions.

For example, cats are obligate carnivores that require high protein diets, while dogs are omnivores with more varied nutritional needs. Cats are also more prone to dental disease, kidney disease and hyperthyroidism as they age. Dogs are more susceptible to joint issues, heart disease and bloat. Infectious diseases like FIV, FeLV and FIP disproportionately affect cats. Parasites like heartworm are much more common in dogs.

With attentive ownership, preventative care and veterinary treatment when needed, both cats and dogs can live happy, healthy lives 10-15 years or longer. Responsible pet owners should partner with their veterinarian for wellness exams, vaccines, dental care, parasite control and early detection of any health issues. Providing enriched diets, proper husbandry and an engaging environment also contributes to better health outcomes.

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