Why Is My Cat So Small and Skinny?

Why Is My Cat So Small and Skinny?

There’s nothing more adorable than a tiny and fluffy cat. However, cats that are too small and skinny can be a source of worry for pet parents. You might eventually start asking, “Why is my cat so small and skinny — is there something wrong with it?”

Your cat may be small and skinny due to its breed and sex. Additionally, its tiny stature can also be caused by a lack of nutrition, a fast metabolism, or high activity levels. Medical conditions, such as dwarfism, hyperthyroidism, anorexia, and diabetes, may also cause your cat to stay small.

In this article, you’ll learn about various causes that can keep your cat small and skinny. Moreover, you can also read how you can help your cat grow bigger and healthier.

Reasons Why Your Cat Is Small and Skinny

Many factors can affect your cat’s stature and weight. Here are some possible reasons why your cat is small and skinny.


Cats come in every size. Several cat breeds are naturally small and slim, even through adulthood. Felines can look underweight, tiny, or kitten-like when in reality, they’re the perfect size for their breed.

Small and slim cat breeds include:

  • Munchkin
  • Cornish Rex
  • Singapura
  • Siamese
  • Minuet
  • Russian Blue
  • Balinese
  • Japanese Bobtail


When talking about a cat’s physique, you also need to consider its sex. Like most mammals, cats display sexual dimorphism. This usually means male felines grow bigger and more muscular than their female counterparts.

While it can be hard to discern the size difference among stray cats, it can be quite noticeable when comparing male and female cats of the same breed.


Dwarfism may be to blame for your cat’s tiny stature. This medical condition can result from various factors, including hormonal deficiencies, genetic mutations, and growth plate abnormalities.

Dwarfism can even be a result of selective breeding. For example, the adorable short-legged Munchkins are believed to be the original breed of dwarf cats.

If you suspect your cat may be a dwarf, it’s a good idea to check its breed or even its ancestry background. Also, don’t hesitate to contact your vet for further examination.


If your cat looks skinny and sluggish, malnourishment is likely the cause. Malnourishment is often caused by one of two reasons:

  • A lack of food.
  • Poor quality food.

Pay attention to your cat food’s nutritional content. Are the ingredients and nutrients appropriate for a cat’s carnivorous diet? Is the food suitable for your cat’s life stage?

Malnourishment won’t just make a cat lose weight. If a cat experiences malnourishment early in life, it may result in growth stunts. As a result, it can stay small and skinny way into adulthood, even if you’ve fixed its diet.

This can be a severe issue. If you believe your cat may be experiencing it, consult your vet immediately and switch to a higher quality, appropriate diet.

Activity Levels

Is your cat the playful and active type? Does it constantly run and play around the house? If so, maybe that’s why it appears small and skinny.Why Is My Cat So Small and Skinny?

Activity levels can greatly influence a cat’s physique. Moving requires calories, and the more your cat moves, the more calories they burn throughout the day. Eventually, this can cause your cat to lose weight and become skinnier.


If your cat is experiencing a sudden drastic weight loss and seems to have lost its appetite, it may be experiencing anorexia.

Anorexia is a decrease or loss of appetite, usually caused by other underlying medical conditions. According to VCA Hospital, there are two types of anorexia:

  • True anorexia
  • Pseudo-anorexia

True anorexia occurs when your feline friend loses its ability to feel hungry. Meanwhile, pseudo-anorexia means it feels hungry and wants to eat but cannot do so due to physical limitations.

If your feline friend has refused to eat within a day or two, there’s a possibility it may be suffering from anorexia. Contact a vet immediately for further examination and treatments.

Worm Infestation

If your cat refuses to eat, it will understandably lose weight. But what if your furry friend has been eating enough? Why does it still look small and skinny?

When was the last time you’ve wormed your cat? A worm infestation may be the culprit, as it can cause drastic weight loss in cats, causing them to be underweight and malnourished.

A cat with worms might exhibit these symptoms:

  • Excessive hunger
  • Weakness
  • Lethargy
  • Diarrhea
  • Sickness

You need to worm your cat regularly to make sure it stays healthy. Here is the recommended cat worming schedule from the International Cat Care Organization:

  • Worm kittens every two weeks when they are three to eight weeks of age.
  • Worm kittens monthly when they are two to six months of age.
  • Worm cats older than six months every one to three months.


Diabetes can also cause a cat to lose weight. This condition impacts a cat’s ability to extract nutrients from the food they eat. As a result, a cat with diabetes wants to eat a lot but cannot gain weight.

Cats with diabetes may exhibit these symptoms:

  • Frequent urination
  • Increased appetite
  • Excessive thirst
  • Unexplained weight loss
  • Weakness and lethargy


Hyperthyroidism is a common problem among older cats, but it can happen to younger felines as well. This condition occurs when the cat’s thyroid gland produces too much thyroid hormone, throwing off your cat’s system balance.

Hyperthyroidism can cause vomiting, increased urination, weight loss, and increased appetite.

If you suspect this may be happening to your cat, consult your vet immediately. With a healthy diet, medication, and appropriate treatments, your cat will start to gain weight and become healthier again.

Gastrointestinal Diseases

Gastrointestinal diseases, allergies, and sensitivities can cause various issues for cats, from pain, diarrhea, gas, to weight loss. Cats with digestive problems usually have a decreased appetite. Moreover, they often have issues extracting nutrients from their food, leading to malnourishment and further weight loss.

How To Check If Your Cat Is Too Skinny

Is your cat actually skinny and underweight?

According to the Association for Pet Obesity Prevention, almost 60% of pet cats across the US are overweight. This may cause pet parents to think their normal cats are abnormally thin. Moreover, it can be hard to tell if your cat is underweight when it has super fluffy fur or a sagging belly.

Fortunately, you can do two easy tests to determine whether your cat is too thin or just right.

The Body Condition Score

The Body Condition Score (BCS) is a tool vets use to evaluate an animal’s weight and fat reserves. It can help you determine whether your cat is too thin, too fat, or just right. Aside from assessing your cat’s appearance, BCS also requires a hands-on assessment.

To score your cat, here are some areas you need to examine:

  • Examine the ribs, spine, and pelvic bones.
  • Examine the cat’s waist, also known as an abdominal tuck.
  • Look at the cat from the side and from above.

The system scores your cat’s body condition from 1 to 9, with 1 being very thin and bony and 9 severely obese. Ideally, a cat should score 4 or 5 on the scale. You can find the BCS scale chart online or at the vet’s office.

Here is an informative video to help you assess your cat’s body condition score:

The Hand Test

If that still sounds confusing, you can use the hand test to help determine your cat’s body condition score. As the name suggests, you only need to use your hand as a reference to assess your cat’s body condition.

First, make a fist with your hand. Then, examine and feel your cat’s spine and ribs. If its spine and ribs feel similar to your protruding knuckles, your cat is likely underweight.

Now open your fist and look at your palm. If your cat’s spine and ribs appear similar to the fleshy pads on your palm, your cat may be of normal weight or even overweight.

Final Thoughts

Your cat’s stature can be influenced by various factors, from breed, age, sex, activity levels, medical conditions, and more. Hopefully, this article has helped you figure out the reason why your cat is small and skinny.

While having a skinny cat doesn’t always warrant a medical emergency, consulting a vet can be very helpful. Always trust your instincts; if you think something might be wrong with your furry friend, don’t hesitate to contact your vet.

Remember that what matters most is having a healthy and happy cat, no matter its size.