Why Is My Cat So Small? When to Worry

As cat lovers, we all appreciate the charm and beauty of different feline breeds, whether large and majestic or tiny and petite. If you have a cat that seems to be on the smaller side, you may wonder, ‘why is my cat so small?’

Many factors can contribute to a cat’s size, including breed, gender, health, and nutrition. In this article, we will explore some potential reasons why your cat may be small and what you can do about it.

Whether you simply want to understand more about your furry friend or are concerned about their health and development, read on to learn more about the reasons behind your cat’s small size.

As your cat approaches adulthood, their growth rate begins to slow. According to Krista Williams, BSc, DVM of VCA, cats typically reach 80% of their adult size at around 30 weeks of age and reach their full adult size at around 40 weeks of age.

While there may not be much you can do to increase the size of an adult cat, it is essential to address any issues that may be causing a kitten or underweight cat to be small.

Understanding the potential causes of weight loss and finding ways to help your cat reach a healthy size can ensure that they grow and develop properly.

Table of Contents

1. Gender

It is common for female cats to be smaller in size compared to male cats. This is due to differences in hormones and genetics between the two genders.

Testosterone, a hormone present in male cats, can contribute to the larger bone size and muscle mass. On the other hand, the absence of this hormone in female cats may result in a smaller overall size. Additionally, certain cat breeds are predisposed to being larger or smaller due to their genetic makeup.

For example, Siamese and Oriental breeds are known for being smaller, while Maine Coons and Persians are typically larger. Ultimately, a cat’s gender and breed can play a role in its size, but it is essential to remember that every cat is unique, and size variations can still be considered healthy.

2. They’re the runt of the litter

If you have a small kitten, especially if you have another kitten from the same litter to compare it to, your kitten may be the runt of the litter.

Runt kittens are usually the smallest and weakest in the group and may have congenital disabilities, which are abnormalities in structure, function, or metabolism.

Some of these abnormalities may not be visible, and with proper care, runt kittens can sometimes be nursed back to health.

However, in the wild, these kittens often do not survive. If you have a runt kitten at home, giving them extra attention and care is important to help them thrive.

Despite their small size, runt kittens are unique and deserve the same love and care as any other kitten.

3. They aren’t eating enough

If you have noticed that your cat is small, it may be a sign that they are underweight. Proper feeding is vital in helping your cat maintain a healthy weight. In the wild, cats are used to hunting small prey and eating several small meals throughout the day.

You can mimic this pattern by dividing their daily food portions into multiple small meals. If you have multiple cats in your household, it is possible that one cat is stealing the other’s food or that the small cat is not eating due to anxiety about the presence of another feline. Solving these issues can help restore your cat’s appetite and normal weight.

Additionally, the location of your cat’s food and water bowls, age, lifestyle, and health can all impact their appetite and weight. Considering these factors, you can ensure that your cat is eating enough and maintaining a healthy weight.

4. You’re feeding them the wrong food

Poor nutrition during kittenhood can significantly contribute to a small size in cats. It is important to ensure that kittens receive the proper nutrition to support healthy growth and development.

When cats are weaned off of their mother’s milk at around 8 weeks of age, it is up to their owners to provide them with a well-balanced, meat-based diet that is suitable for their age, health status, and lifestyle. If you have adopted an adult cat that is small in size, it is possible that they were not receiving enough nutrition in the past, either due to a lack of access to food or a diet that was not nutritionally balanced.

It is also possible that the type of food you are currently feeding your cat is not meeting its nutritional needs, which can lead to weight loss and small size.

Paying attention to your cat’s eating habits and possibly even feeding them separately can help you identify and address any issues related to their nutrition.

5. Their breed is naturally small

If your cat is a stray with unknown origins, its ancestry may be connected to one of the following small cat breeds: Siamese, Devon Rex, Cornish Rex, Singapura, or Sphynx.

These breeds are known for their small size and unique physical characteristics. Even if you do not have a purebred cat, understanding the potential breeds in your cat’s ancestry can help you better understand its size and characteristics.

  • Siamese: Siamese cats are typically slender and graceful, with an average weight of 5-10 pounds for males and 4-8 pounds for females. They typically have long, slender bodies and legs, with a wedge-shaped head and large, almond-shaped eyes.
  • Devon Rex: Devon Rex cats are known for their small, lithe bodies and soft, curly coats. They typically weigh around 5-10 pounds and have a short, athletic build.
  • Cornish Rex: Cornish Rex cats are similar to Devon Rex cats in terms of their small size and soft, curly coats. They typically weigh around 5-9 pounds and have a slender, athletic build.
  • Singapura: Singapura cats are one of the smallest breeds, with an average weight of just 5-8 pounds. They have a petite, slender build and large, expressive eyes.
  • Sphynx: Sphynx cats are known for their hairless bodies, which give them a small, slender appearance. They typically weigh around 6-12 pounds and have a muscular, athletic build.

6. They have dwarfism

Feline dwarfism, including the Munchkin breed, has garnered scientific interest as researchers seek to understand this condition in animals and humans better.

Munchkin cats are believed to have a genetic defect called pseudoachondroplasia, which results in short limbs. While The International Cat Association recognizes Munchkin cats as an official breed, the Cat Fanciers’ Association and American Cat Fanciers Association do not.

Other cats with dwarfism may have shortened limbs, unusual proportions, or underdeveloped parts, such as Grumpy Cat and Lil BUB.

If your cat is small and has a disproportionate body with short legs, it may be a Munchkin or have a form of dwarfism. Regular visits to the vet can help you monitor any health issues related to their small size.

7. They have parasites

Parasites can also be a potential reason for a small size in cats, especially in kittens. Common worms that can affect a kitten’s growth and development include hookworms, tapeworms, and roundworms.

Symptoms to watch out for include weight loss, diarrhea, vomiting, a bloated belly, constant coughing, and worm segments in the stool or anus. It is crucial to take newly adopted kittens to the vet and provide them with anti-parasite medication to prevent and treat potential parasite infections.

Addressing parasite issues early on can help ensure your kitten grows and develops to their full potential.

8. They have diabetes

If your cat is experiencing weight loss despite maintaining a normal appetite, it may be ill. This could be a sign of diabetes or hyperthyroidism, which are more common in middle-aged and older cats. In addition to weight loss, other symptoms of these conditions may include increased appetite, thirst, urination, vomiting, diarrhea, and changes in coat appearance.

If you notice any unusual behavior in your cat, you must consult a veterinarian for proper diagnosis and treatment. You can help ensure that your cat stays happy and healthy by addressing health issues promptly.

How Can I Maintain My Cat’s Health and Weight?

Maintaining a healthy weight and size is essential for cats to support their overall health and well-being. There are several steps that cat owners can take to ensure that their feline companions are growing and developing typically:

  1. Provide a balanced diet: A nutritionally balanced diet is essential for supporting proper growth and development in cats. This should include high-quality, meat-based protein sources and the necessary vitamins and minerals. Choosing a diet appropriate for your cat’s age, breed, and lifestyle is important.
  2. Monitor food intake: Pay attention to how much your cat is eating and ensure that they receive the appropriate amount of food for its size and needs. If you have multiple cats, you may need to feed them separately to ensure that each cat receives the proper amount of food.
  3. Monitor weight: Regularly weigh your cat to ensure that they maintain a healthy weight. Consult with your veterinarian if you notice any sudden weight changes.
  4. Provide regular exercise: Cats, like all animals, need regular exercise to maintain a healthy weight and overall physical health. Providing toys and other interactive objects can help stimulate your cat’s instincts to hunt and play.
  5. Regular visits to the veterinarian are important for ensuring that your cat is healthy and receiving the necessary preventative care. Your veterinarian can also help monitor your cat’s weight and development and address any issues that may arise.

By following these steps, you can help ensure that your cat maintains a healthy weight and size.


Several factors can impact a cat’s size, including breed, gender, nutrition, and health issues. It is important to understand the potential reasons behind your cat’s small size to address any underlying issues and ensure they receive the proper care.

By providing a balanced diet, monitoring food intake and weight, regular exercise, and visiting the veterinarian regularly, you can help your cat maintain a healthy weight and size and live a happy, healthy life.

Ashley is the co-founder of CatProductGuide.com. She is a professional writer, whose work has been seen in many top publications and websites, like Digital Trends, Opposing Views, Men's Health, and more. She is passionate about all animals, and loves her cats Felix and Lola. Ashley enjoys finding the best products and foods to ensure they're living their best lives possible!

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