How To Tell If Your Cat Is A Runt: 5 Signs to Look For

Many litters come out with runts. A runt is the smallest and weakest of the born kittens. While newborn kittens are fragile, runts are more vulnerable. Knowing how to tell if your cat is a runt will allow pet owners to give the proper care the feline needs. Runts are not a lost cause – you can still give them a happy and fulfilling life.

I’ve had many cats ever since I’m a child, so I know well when a kitten is a runt. I also volunteer at a local shelter from time to time, where many runts are either rescued or surrendered due to their failing health.

how to tell if your cat is a runt

Signs that a cat is a runt

Contrary to some beliefs, not all litters have runts. Many turn out fine and all the kittens are equally healthy. But if you’re adopting, it will help a lot if you’ll know whether your cat is a runt or not. The following are some of the common signs to look for:

runt cat

1. Smaller than normal size

One of the tell-tale signs that a cat is a runt is its small size. For adult cats, you’ll easily see that they are smaller than other kitties of the same age. This is due to poor nourishment during and after pregnancy. Learn more here how to tell if your cat is pregnent

However, you have to understand that some cat breeds are smaller than others. It’s best to see the parents or at least the other kittens in the litter so you can make a comparison.

2. Inability to suckle

Inability or difficulty suckling is a sign that a kitten is a runt. This is due to their weaker and smaller bodies. As the other kittens struggle to reach the mother cat’s nipples, the runt is typically left behind. In most cases, the owner has to interfere through syringe feeding to ensure that the runt gets to eat. learn Here how to force feed a cat

Many mother cats will help the runt suck milk from its nipples. Unfortunately, there are cases where the mother cat completely rejects or abandons the runt because of its lower chance of survival.

3. Physical deformity

If the cat has a physical deformity, there’s a high chance that it’s the runt of the litter. Some of the runt kittens I’ve seen have crooked legs, bulging eyes(Read here how to tell if your cat is blind), uneven paws, and underdeveloped organs. In fact, the runt in my cat Watson’s litter had crooked legs. Fortunately, a family took the kitty in and had him treated by the vet.

You will notice the runt will have difficulty walking or moving. It also tends to move less due to the discomfort brought by the congenital deformity. This will contribute to the runt’s failure to receive proper nutrition from its mother cat.

4. Obvious weakness

Runts are often weak. While the other kittens are playing and wrestling around, the runt can be seen sitting on a corner. This is obviously seen on the initial days after birth since the healthy kittens will often move to locate their mother.

Also, runts often have underlying illnesses, which makes them even weaker. This is the reason why this kitty requires intensive attention to increase its chance of survival.

5. Fading Kitten Syndrome

The Fading Kitten Syndrome (FKS) is very common among runts born by undernourished mothers. Take note that the entire litter can have FKS, not just the runt. But since runts are smaller and weaker, they are more likely to succumb to this condition.

The Fading Kitten Syndrome causes weakness, extremely poor appetite, isolation from the litter, and malnourishment. It’s called ‘fading kitten’ because this condition kills a lot of newborn kittens slowly as if they are fading.

Proper care is needed to save a runt showing signs of FKS. It’s best to involve the vet if you suspect that your cat has this condition.

Is it bad to pick the runt of the litter?

No, it’s not really bad to pick the runt of the litter if you’re planning to adopt a cat. While they are smaller and weaker than the others, it doesn’t mean they won’t be amazing pets. Proper care will help the runt regain its healthy so it will become stronger.

When deciding to pick the runt, you should check its interaction with the mother cat. If the mama cat nurses and grooms the runt, it’s a good sign that the runt can survive and live normally.

Meanwhile, rejected runts have to be fed by the breeder. This means that the kitty won’t get its mother’s milk. This works, too, but make sure that you get the kitty checked by a veterinarian.

Also, you should only deal with a responsible and licensed breeder. Legitimate breeders run tests on all the kittens to ensure that they are in good health. Also, they won’t give you a sickly kitten, no matter if it’s the runt or not.

Is it bad to pick the runt of the litter

For those who are adopting from a shelter, picking the runt is a noble choice. As you know, not all shelters or rescue organizations have enough funds to sustain all the animals. The weakest often end up not getting adopted. And when that happens, some shelters will euthanize them as more and more animals arrive.

Remember that the runts can still be the stars of the litter. You just have to care for them properly.

How to care for a runt

If you have a runt cat, it’s important to formulate a plan on how to raise it. The following are some of the things to keep in mind:

How to care for a runt cat

Always keep the vet involved

A runt is like a sickly child. You always have to stay connected with the doctor. Before bringing the runt cat home, visit the vet’s clinic for a comprehensive checkup. This way, the vet will diagnose if the kitty has underlying health problems or organ issues.

Feed multiple times a day

Also, it’s important to feed a runt multiple times a day in small servings. Ideally, you should purchase a kitten formula if the mother cat is no longer around. Learn here how to feed a toothless cat

But if the runt is under a month and its mother is still nursing, it’s best to let it suckle on its mama. The kitty will need some help to reach the nipple and ensure that the other kittens will not steal his spot.

Keep the runt warm

Kittens can’t control their body temperature during the first weeks of life. Runts are more vulnerable because they are weak, and cold temperatures can easily become deadly for them.

For this, you can use a heating pad, but make sure that it’s not too hot for the kitty. Blankets are also a big help.

Monitor 24/7

Lastly, always monitor the runt. If the kitty is only a few weeks old, it’s not advisable to leave it alone at home. You have to keep tabs on its condition 24/7. Take note that even the litter’s healthy members will require round-the-clock monitoring between 1 to 8 weeks. After that, you can wean the kitty from the kitten formula and transition it to kitten food. Please read here how long can you leave a cat alone

Can there be more than one runt in a litter?

Yes, there can be more than one runt in a litter. However, the ‘true runt’ is often just one. This is more common on mother cats with very large litters. Since there are many kittens that compete for nutrition, more than one of the members may turn out underweight and small.

However, just because a kitten is small doesn’t mean it’s automatically a runt. You have to check its health. If it doesn’t have problems suckling, the size is just probably normal.

Do runt kittens stay small?

Yes and no. Some runts grow to normal size. Meanwhile, others remain smaller than their ideal size, but it doesn’t mean that the cat isn’t healthy. It’s possible that it just got stunted, which occurs to other animals and humans as well. Learn more here why is my cat so small

How long do runt cats live?

A runt can live as long as any healthy cat. The rule of thumb is that if the runt made it to six weeks, it’s likely going to survive. About how long, it depends on the kitten’s general health and the care it will receive.

As long as they are provided proper care and nutrition, a runt will become a healthy feline. However, you have to watch out for health problems. And if the runt has a physical deformity, it will not develop properly. This could be tied to a more serious health problem.

Do runt cats have health problems?

There’s a very high chance that the runt of the litter will have heart defects. Umbilical hernias and deformities are also possible. If you are getting the kitten from a breeder, make sure that he or she provides a full report on the cat’s health.

On a lighter note, some runts will not have any serious problems and will thrive under proper care.

Do mother cats reject runts?

There’s a chance that a mother cat will reject the runt because of its poor health. It’s said that mother cats can detect the chance of survival of their kittens. And if the runt is too weak, the mama cat will likely abandon or reject it. Still, there are instances when the mother cat gives more attention to the runt. learn here why does mother cat move only  one kitten

Take note that a mother cat can reject any of its kittens for some reason. And when this happens, you should take care of the kitty to ensure that it will survive.

Are runts always born last?

Most of the time, runts are the ones born last because they are also conceived later than other litter members. This makes them weaker and smaller, with some having underdeveloped skeletons and body organs.

However, the runt doesn’t have to be born last all the time. There are instances when runts are born ahead of other healthy kittens. This is the reason why the birth order isn’t used to define which one of the kittens is the true runt.


Knowing how to tell if your cat is a runt goes beyond the notion of which kitten is born last. You have to check the kitten’s size and health to identify the weakling among the group. Despite their weaker bodies, runts can survive and become beautiful cats. Giving the weakest littler member a chance in life is one of the greatest joy of being a cat owner.

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