Why Is My Cat Thin at The Back End

Why Is My Cat Thin at The Back End

We’re all easily attracted to affectionate cats that are pudgy and healthy. But sometimes it can be deceiving because a cat can look big but it’s actually mostly fur. If our pet cats start to get thin especially at the back end we may start to worry.

How to determine if your cat is thin at the back end 

A healthy cat’s back or rear end gives an impression of support and strength. The entire back end which includes the buttocks and thigh should be covered with fur, sturdy and well-muscled. It is where most of the vital organs are located such as the kidney, small intestine, colon, stomach, liver, and spleen.

If you notice that your pet’s back end is saggy, sunken, and looks abnormal then it may be an indication of being too thin. Also, you may try to feel your pet’s spine, and if the vertebrae seem like there is nothing on top and difficult to feel then your cat has a thin back end.

Why do cats usually get thin including the back end?

Cats have varied eating habits and patterns. Some like to eat a lot, some are finicky when it comes to food while still others like to eat at various times during the day. Generally, these are the usual reasons why cats lose weight and get thin at the back end:

1. It may be due to an underlying illness or disease.

You may think that your pet is okay because it’s eating normally and doesn’t manifest major behavioral changes except for weight loss. If this is the case then your pet may have a disease or illness. These include the following:


It results from the inability to produce insulin which balances glucose levels. Other signs aside from weight loss may include urinating more than usual, drinking lots of water, and looking sluggish. 


It is caused by a benign tumor in the thyroid glands resulting in elevated thyroid hormone levels. Older felines are more prone to this illness. Other signs that your pet has this illness include frequent drinking of water, excessive urination, diarrhea, and vomiting. 


Certain cancers are common in pet cats such as soft tissue sarcoma and lymphoma, a type of blood cancer. Aside from getting thin, other signs may include difficulty in urinating, defecating, and the appearance of lumps or tumors. 

Gastrointestinal tract and digestive disease

This disorder minimizes the digestion and absorption of food and modifies its passage to the digestive system. The types of gastrointestinal disorders include colitis, pancreatitis, and irritable bowel syndrome. The presence of parasites or worms is also under this category and could be the culprit why your pet cat is getting thin. Other symptoms may include vomiting, diarrhea, constipation, and flatulence.

Feline infectious peritonitis

This is a viral disease caused by a coronavirus that attacks the intestinal walls. The symptoms include weight loss, excessive urination, and distended abdomen. 

2. Due to loss of appetite.

If your pet is showing a loss of appetite and doesn’t show interest in food then it’s a cause for great alarm and worry. Loss of appetite or anorexia is characterized by a change in eating habits and/or a consistent refusal to eat. These may be the potential reasons: 

  • It has dental issues and its tooth or mouth may be painful.
  • It’s not feeling well. 
  • Something is stuck in its airways like a hairball or it may have ingested a foreign body or object. 
  • It doesn’t like the texture, flavor, or taste of the food. 

3. Due to stress, depression, or anxiety.

Pet cats may also lose weight because of psychological depression, stress, and anxiety.  They may get depressed due to loneliness, changes in their environment or routines, and even the death of a companion animal or family member. The usual causes of stress in cats include a dirty litter box, a noisy environment such as remodeling projects, and loud parties at home as well as being in unknown spaces. Competition for resources and inadequate territory are also possible causes, especially if it’s a multi-pet household. 

Cat breeds with a slender physique

However, there are cases where your pet cat, although it may have a thin back end, is perfectly okay and has no weight problems after all. This is because there are cat breeds that have a natural slender physique even as they appear to be unusually thin for some people. Here are just some of them:

Devon Rex

This hypoallergenic breed originated in Europe. Aside from being slender, it has big ears, short hair, a thin tail, thin limbs, and has an extrovert and affectionate nature. 


This breed originated from Russia and has an average weight of 7 to 11 pounds. It has a thin tail, big ears, and hairless. It’s referred to as the oriental version of the Sphynx and has a calm, affectionate and extroverted character. 

Oriental shorthair

This cat breed originated from Thailand. It is said to be a cross-breed of the Siamese and British or American shorthair breeds. It has a muscular body, usually weighs 5 kgs., affectionate, and makes powerful vocalizations or sounds. 

Cornish Rex

It originated from the United Kingdom and best known for its striking looks and endearing personality. Its life expectancy is 15 to 18 years.

Russian blue

This is one of the most popular cat breeds because of its striking bright blue color and intense green eyes. It has a calm, affectionate, curious, and intelligent personality. 

What to do if your cat is thin at the back end

If your pet cat looks and acts normal but has a thin back end then here’s what you should do to address the situation promptly:

1. Visit the veterinarian.

A visit to your vet is the first step that you should take to check the matter. Your vet will perform a physical examination along with laboratory and blood tests. These are needed to come up with the necessary diagnosis, treatment, and medication.

2. Give your pet high-calorie and nutrient-rich food.

Sometimes all it takes is a nutritious and protein-rich food to help your cat gain weight again. Try Iams Proactive Health High Protein Chicken and Salmon Recipe Dry Cat Food. It’s enriched with fatty acids for shiny fur, has no artificial preservatives, and contains minerals for strong bones and teeth. High-calorie supplements that come in gel form may also be given but make sure to consult it with your vet first. 

3. Administer an appetite stimulant. 

An appetite stimulant like Mirtazapine may be given to your pet cat. This comes in pill form and transdermal formula which makes it easy to absorb. However, make sure you have the nod from your vet before giving it to your pet. 

4. Make food more flavorful and delectable. 

Encourage your pet cat to become interested again in food by enhancing the flavor and using add-ons. These may be in the form of tuna or clam juice, dried tuna flakes, powdered tuna, and oregano flavoring. 

5. Keep your pet cat hydrated.

Be sure to have ample water nearby so your pet can drink anytime and stay hydrated. Usually, dehydration can lead to a loss of interest in eating. Placing an automatic water dispenser in a strategic location can also encourage your pet cat to drink water anytime. 


As pet owners, we all want a healthy and happy cat that’s why when our pets have a thin back end we tend to worry a lot. If initial efforts to treat it remain fruitless and your cat still doesn’t gain weight, it’s wise to bring them to the veterinarian. Your vet will do a thorough examination to ascertain if there’s a cause for alarm or not.