Inbreeding in Cats: Signs, Lifespan of Inbred Cats & More

Have you wondered what causes birth defects in cats? I mean why some cats are obviously different from others? This is as a result of an unusual mating practice within the family of the cat termed inbreeding. The offspring of such practice are called inbred cats.

The truth is cats have no taboo against mating with very close relatives, such as parents, siblings, niblings (nieces and nephews), and grandparents. However, the major concern for cat owners and breeders is the detrimental effects on the health and well-being of kittens produced from such mating.

This article will provide an in-depth look at inbreeding in cats. It covers the signs of inbred kittens, specific health effects seen, impacts on lifespan, and general care recommendations for any inbred cats taken into homes.

Inbreeding in Cats

What is Inbreeding in Cats?

Inbreeding in cats refers to the mating of closely related cats, such as siblings or parents and offspring. It results in decreased genetic diversity and can increase the chances of offspring inheriting genetic diseases or undesirable traits.

Specifically, inbreeding is when two cats who are closely related (families) are mated together. This includes mating between siblings, parents and offspring, cousins, and other close familial relations. When two genetically similar cats mate, it concentrates their genetics and reduces the gene pool.

Inbreeding reduces heterozygosity, which is beneficial for genetic diversity. With less genetic variation, undesirable recessive traits are more likely to occur in inbred kittens. These traits can include health problems like heart defects, respiratory issues, and susceptibility to disease.

Inbreeding also allows positive traits like desirable coat colors or body types to be passed down and concentrated. However, the risks often outweigh the benefits, which has led to inbreeding being discouraged in cat breeding.

Responsible cat breeders avoid inbreeding cats or only do so infrequently and carefully to fix desirable traits within a breed. Inbreeding can still occasionally occur when female cats mate with male relatives in an uncontrolled environment.

Why Does Inbreeding Occur in Cats?

Inbreeding is the mating of closely related cats, such as siblings or parents and offspring. It can occur both intentionally and accidentally:

– Accidental Inbreeding: This often happens when cats are allowed to roam and mate freely. Their natural tendency is to mate with family members if no unrelated mates are available. This is especially common with stray cat populations or in rural areas where few non-related cats live nearby.

– Intentional Inbreeding: Some cat breeders intentionally breed closely related cats in an attempt to pass down desirable physical traits or fix certain features. However, this also concentrates on negative genetic mutations. Reputable breeders avoid it due to health risks.

Inbreeding is more likely to happen when the gene pool is small, so cats have limited mating options. Geographic isolation and limited introduction of new cats also increase the chances of related cats mating. Responsible breeding reduces its likelihood.

Signs That a Cat is Inbred

Some physical signs that a cat may be inbred include facial deformities and limb deformities. Here are some specific signs to look out for:

  • Misaligned jaws: This can cause undershot or overshot jaws where the upper and lower jaws do not properly align.
  • Cleft palate: A split in the roof of the mouth.
  • Twisted limbs: Limbs may be crooked or bent at odd angles as a result of malformed joints.
  • Missing teeth: Inbred cats may fail to develop some adult teeth.
  • Extra digits: Polydactyly, where a cat has extra toes or fingers, is common in some inbred cat lines.
  • Eye deformities: Crossed eyes, small eyes, or protruding eyes may occur.
  • Microphthalmia: Underdeveloped eyes resulting in vision impairment.
  • Hydrocephalus: Enlarged, dome-shaped skull due to excess fluid in the brain.
  • Heart defects: Such as valve malformations.
  • Spinal deformities: Such as short, kinked, or fused vertebrae.
  • Facial asymmetry: Uneven facial features.
  • Fold in the ear: Folded over part way up the ear.
  • Smaller size: Inbreeding can result in stunted growth.
  • Lack of fur: Patchy fur development.

These are the signs of inbreeding in cats. The more physical deformities present, the more likely inbreeding is the cause.

Health Effects of Inbreeding in Cats

Inbreeding can have serious deleterious health effects in cats. Some of the main health issues that are seen at higher rates in inbred cats include:

1) Respiratory issues: Inbred cats often have higher rates of respiratory infections and problems. Their respiratory systems may not develop properly, leaving them prone to issues like pneumonia or feline asthma.

2) Heart defects: Congenital heart defects are more common in inbred cats. Defects like ventricular septal defects, atrial septal defects, and valvular dysplasia can seriously impact a cat’s health and longevity.

3) Immune system problems: Inbreeding suppresses the immune system, making cats more prone to infections, viruses, and diseases. Their bodies are less able to fight off common kitten illnesses, viruses, and other pathogens.

Other health issues seen more often in inbred cats include skeletal deformities, neurological problems, digestive issues, and cancer. Inbred kittens often suffer neonatal mortality and shorter lifespans. They are also prone to congenital defects, immunodeficiency, organ dysfunction, cancers, and behavioral abnormalities.

Lifespan of Inbred Cats

Inbred cats tend to have a shorter lifespan compared to non-inbred cats. This is due to the various health issues that arise from inbreeding.

Some studies have shown that inbred cats may live approximately 2-3 years less on average compared to non-inbred cats. However, the lifespan reduction can be even more significant depending on the degree of inbreeding and how many negative recessive genes are expressed as a result.

Severe inbreeding can lead to kittens with multiple health defects that sadly do not survive long after birth. Moderately inbred cats are likely to develop conditions like heart disease, cancer, kidney disease, and diabetes at a younger age. This puts them at risk for earlier mortality.

While the average lifespan of a healthy cat is around 15 years, an inbred cat’s lifespan is often shortened to 10-13 years. Proper care and nutrition may help extend an inbred cat’s life slightly, but their genetic disposition remains a limiting factor.

Monitoring an inbred cat closely and treating any emerging health issues early can potentially gain them a little more longevity. But ultimately their abbreviated life expectancy is tragic and further underscores why inbreeding cats should always be avoided.

Behavioral Effects of Inbreeding

Inbreeding can have significant effects on a cat’s behavior and temperament. Some common behavioral issues seen in inbred cats include:

– Increased Aggression: Inbred cats often display higher levels of aggression towards other cats, animals, and even their owners. The increased homozygosity from inbreeding seems to amplify dominant traits like aggression. Inbred male cats in particular can be very aggressive and difficult to handle.

– Anxiety & Fearfulness: Inbred cats are also more prone to anxious behaviors like excessive meowing, furniture scratching, and urine marking. They tend to be more fearful of unfamiliar people, objects, and environments. This is likely due to the lower genetic diversity reducing their ability to adapt to change.

– Other Issues: Other behavioral problems associated with inbred cats include increased timidity, irritability, obsessive behaviors, stress, and difficulty socializing with other pets. The abnormal behavior can make inbred cats destructive in the home or unable to be handled.

Proper socialization and training from kittenhood are important to minimize behavioral issues in inbred cats. It’s important to provide a calm, soothing environment and appropriate enrichment if caring for an inbred cat prone to anxiety or aggression issues.

Related: Best Ways To Manage And Calm An Aggressive Cat

Reproductive Issues in Inbred Cats

Inbreeding increases the chances of reproductive issues in cats. Some of the main reproductive problems seen in inbred cats include:

– Lower fertility rates: Inbred cats often have reduced fertility compared to outbred cats. Male inbred cats can have low sperm counts or high numbers of abnormal sperm. Female inbred cats may ovulate less frequently or have higher rates of resorbing fetuses. Inbred cats are less likely to reproduce.

– Higher neonatal mortality: Even if inbred cats get pregnant and give birth, their kittens are less likely to survive. Mortality rates in newborn kittens can be much higher with inbred parents. Newborns may be born weak, undersized, or with genetic defects incompatible with life.

– Smaller litter sizes: Inbred cats that do successfully give birth often have fewer kittens per litter. Litter sizes tend to be smaller on average compared to cats without inbreeding in their pedigrees.

– Birth defects: Due to higher rates of detrimental recessive genes, inbred kittens have a greater chance of being born with physical defects. Common birth defects in inbred cats include cleft palate, heart malformations, limb deformities, and cognitive impairments.

Proper outcrossing programs and responsible breeding practices can help reduce the frequency of reproductive issues caused by inbreeding in cats. However, inbred cats may struggle more with fertility and successfully producing healthy litters.

How to Care for an Inbred Cat

Caring for an inbred cat requires some special considerations to support their health and well-being. Here are some tips:

– Close veterinary monitoring: Inbred cats are prone to more health issues, so work closely with your vet to monitor their health with regular checkups. Vaccinations, dental exams, bloodwork, and other tests allow early detection and treatment of any problems.

– High quality nutrition: Feed a high-quality diet and keep their weight in a healthy range. Good nutrition supports overall health and immune function. Consult your vet on the ideal food for your cat’s needs and age. 

– Enriched environment: Inbred cats may have social or behavioral challenges, so create an enriched home. Provide scratching posts, cat trees, and toys, and interact with them often. This mental stimulation can reduce anxiety and stress. 

– Limit stress: Changes and unfamiliar environments can be overwhelming, so minimize changes to their routines. Reduce noise, commotion, and introductions to new pets. A calm, stable environment helps them feel secure.

– Patience and love: Special needs cats require more patience and compassion. While inbred cats may have health or behavior challenges, they still need and deserve caring homes. With gentle handling, they can live happy lives as beloved pets.

Related: Runt Kitten: Life Expectancy, Feeding, Care, & Health Issues


The health effects of inbreeding essentially reduce the cat’s overall fitness and ability to thrive. With an empathetic, responsible owner, an inbred cat can live happily despite genetic limitations. I believe this article gives sufficient information on inbreeding in cats.

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