How To Tell If Your Hamster Is Sick? [6 Signs]

Thanks to an article written by World Atlas, we know that hamsters are definitely within America’s top five favorite pets, which means it’s likely that you either own one or have had one in the past. They are fun, rewarding, and straightforward to keep as pets. However, these domestic rodents are somewhat fragile creatures that are prone to a multitude of health issues or troubling behavior.

Here are six indications that your hamster might be sick:

  1. It’s experiencing extreme hair loss or has bald patches.
  2. Its eyes appear to be bulging or overly large.
  3. It has visible injuries, potentially self-inflicted.
  4. It’s lethargic, unresponsive, or behaving unusually.
  5. It won’t eat.
  6. It’s antisocial or aggressive.

If your pet is showing any of these signs, I recommend that you contact a veterinarian immediately or follow the tips in this guide to assist your furry friend. You must also note that hamsters can also exhibit behavior that seems abnormal or dangerous but is, in reality, relatively harmless. These kinds of irregular behavior, whether severe or not, will be covered in depth in the following article.

How To Tell If Your Hamster Is Sick?

how to tell when your hamster is sick
how to tell when your hamster is sick

1. It’s Experiencing Extreme Hair Loss or Has Bald Patches

The primary way to health-check your hamster is simply by inspecting its appearance. A healthy hamster should have a clean and clear coat of fur, quick and attentive eyes, and a mouth free of scabs or hindrance.

The United States-based veterinarian service Caring Pets ranks an unhealthy coat among the top signs of a potential health issue. If your hamster’s coat is losing smoothness or texture for ruffled or sagging hair, it could indicate a severe health problem.

Furthermore, in more extreme circumstances, a hamster may suffer from alopecia, in which it will experience significant hair loss.

This can be a result of a direct disease or issue, such as:

  • Ringworm
  • Lesions
  • Sarcoptic mange
  • Mites

Of course, it may also reflect a much larger overarching health issue, like organ diseases or nutritional deficits in its diet. A lack of protein or iron can significantly impact the health of a hamster’s coat.

What is quite important to note is that hamsters will naturally shed their fur. If you find slivers of your pet’s hair about its cage, it does not necessarily mean they are ill. Nicole Cosgrove from the international pet writing blog Pet Keen confirms this in her article centered on the American pet.

However, if you see clumps of stained or wet hair, it is recommended that you further your attention toward your pet’s health.

To extend upon this, if the fur toward the animal’s rear is constantly wet, it may be a case of diarrhea. This may be due to a sudden change in diet or parasites like mites, ringworms, and tapeworms. 

Read How To Clean Hamster Poop

2. Its Eyes Appear to Be Bulging or Overly Large

Another simple way to spot signs of illness is by checking out your hamster’s eyes.

Although these issues are usually independent infections, you must treat them seriously; else, the animal will succumb to a total loss of sight in one or both eyes.

As described by PetMD, Proptosis is the “bulging of one or both eyeballs from the socket.”

This primarily occurs due to one of two reasons:

  • Your hamster has suffered trauma to the eye. This may come from poor handling, where the owner will hold the head of the creature too tightly, or from the infighting of hamsters housed together.
  • Your hamster has contracted an infection in its eye. This risk primarily arises if you keep the pet in a dirty or moist environment.

It is advisable that if any of these signs are present in your hamster, you should seek help from a professional veterinarian immediately.

3. It Has Visible Injuries, Potentially Self-Inflicted

Furthermore, it would be best if you stayed wary of skin lesions and sores on your hamster, as these injuries can lead directly to a fatal infection.

Minor and easily unnoticed incisions can cause previously mentioned issues like mites or ringworm.

Furthermore, infectious cuts can create abscesses beneath a hamster’s skin, causing a bumpy texture and pus-filled wounds. These injuries can often go away on their own account; however, if this is an issue that occurs regularly in mass effect, it may be worthwhile to contact your local veterinarian.

Cuts and scrapes on a hamster can also be self-inflicted. If your hamster’s cheek pouches are impacted, it may claw at its face to try to remove the food. That can result in injuries to your pet’s face. Additionally, if your pet has fleas or mites, it may scratch itself to relieve the itching.

Too much scratching can lead to cuts and scratches.

Read How Much Does It Cost To Take a Hamster to the Vet?

4. It’s Lethargic, Unresponsive, or Behaving Unusually

A more practical presentation of sickness in your hamster is a sudden and extreme change in their behavior.

A healthy hamster will commonly exhibit attentive and playful mannerisms. However, this attitude may be extinguished if an underlying health issue is afoot.

According to Dr. Sara Ochoa, in a statement for American pet superstore Petco, sickness in hamsters is shown in their behavior far before it is seen in their physical appearance.

A hamster may abruptly become lazy, slow, or uninterested in its owner if it suffers from an internal disease or infection. It will stop rummaging and playing day and night and refuse to move.

While most will initially handle their pet to enthuse them, this can worsen the state of the animal. They are likely staying still for a good reason.

I recommend having them checked out by a veterinarian if this behavior persists and moving them to and fro with gentle caution.

While often caused by infection or disease, some unique circumstances may cause the same poor impact.

Neglect of the pet is commonly the case, especially when the animal is entrusted to younger owners. You must make sure to provide a substantial amount of attention for your hamster for the ideal environment.

Another reason for lethargy can be a drop in temperature. Sure, hamsters will naturally hibernate through colder months in the wild; however, this does not mean that your domestic pet should do the same.

Inducing hibernation by not providing a heat source will make the creature’s life harsher and harder.

This fact is reinforced by the professional word of Aspen Commons, Colorado, in their evaluation of hamsters and the cold.

Read Why Is My Hamster Losing Weight?

5. It Won’t Eat

A significant issue caused by various ailments is a hamster refusing to eat or intake water.

Not only does this commonly represent health issues, but it will also further cause a detriment through the starvation or dehydration of the animal. They are not resilient creatures and will be significantly hindered if this occurs.

This response to sickness is very common and should be treated immediately with the help of a professional veterinarian.

Causes include:

  • Ringworm
  • Tapeworms
  • Mites
  • Organ diseases

This may also occur if the hamster cannot eat due to trauma or overgrown front teeth. A healthy hamster with a sufficient diet should not encounter this issue and, if well-kept, should have plenty of things to gnaw on and wear down their incisors.

However, if you do face this issue, according to Omelet U.S., you should take your pet to the vet so they can have their teeth mended to working order.

Check out, Why Is My Hamster Scared of Me?

6. It’s Antisocial or Aggressive

Finally, a hamster may display an apathetic attitude toward you or any roommates it may be kept with if afflicted by disease or illness.

You can see this more easily if the pet in question is kept with others, as it will consistently demonstrate its want to isolate. However, even when kept solitary, by simply interacting with it, this behavior may be seen if the creature suffers from a health issue.

The pet may hide or actively flee from you if you come near it. Sometimes it may even become aggressive if attempts to handle it persist (though this is rare and hardly dangerous for the owner).

You should understand that these things are not always caused by illness: if the pet is new, it may need time to acclimate to being handled.

how to tell if your hamster is sick or dying
how to tell if your hamster is sick or dying

Read What Can Kill a Hamster

Common Illnesses To Be Aware of in Hamsters

Some common illnesses that are tied to the constitution and behavior of the animal have already been named throughout this article.

However, this section will briefly define the most common and dangerous diseases and infections you should know as a hamster owner.

This information is comprehensively expanded upon within the paper Small Rodents: Common Diseases by Christoph Mans, a Clinical Associate Professor of Zoological Medicine from the University of Wisconsin, and The Biology and Disease of Hamsters from the U.S. National Library of Medicine and Institutes of Health.


Enteritis is the inflammation and irritation of the small intestine. As touched on previously, symptoms include: “diarrhea, perianal soiling, dehydration, emaciation, and poor fur condition.” This affliction can be dealt with by the application of antibiotics, as well as veterinary assistance in giving the hamster fluids and beneficial solid foods.


Pneumonia is a bacterially caused respiratory infection that may cause fluid discharges from the animal’s nose and eyes. It may also make it hard for the hamster to breathe, eat, or move. Seek immediate treatment if you suspect your hamster is exhibiting these symptoms.


Mites are parasitic organisms that will use hamsters as hosts. They are often non-lethal but will cause many detrimental issues, like skin damage and infections, and promote further infections within the animal’s ears, nose, and genitalia.

Despite varying degrees of severity between these health issues, I recommend that you contact a veterinarian immediately if you spot any of these symptoms.

Read How To Empty Hamster Cheek Pouch?

Other Causes for Irregular Behavior in Hamsters

If your hamster demonstrates some of these symptoms, but you’re still unsure if there is an issue with its health, there are still a few circumstances that you should consider.

Your Hamster Will Be Impacted by Its Age

An inevitable factor that will cause a series of behavioral and well-being issues is age.

According to the University of Wisconsin’s Christoph Mans, the average lifespan of a hamster is one and a half to two years. Of course, that is given that the pet is kept well – and as previously established, they are prone to illnesses that can hinder that duration.

In any case, as your pet nears the end of its life, it will encounter health issues naturally.

They will most likely experience alopecia and lose a decent amount of hair as they age. They may also find it harder to eat and stay energetic for long periods.

However, your hamster will also grow more susceptible to severe illnesses. Therefore, you should not neglect to have them evaluated by a veterinarian if symptoms present themselves.

Read Why Does My Hamster Stink?

Make Sure Your Hamster Is Not Pregnant

Pregnancy is a consideration only applicable if your hamster is female and housed with or near male counterparts. It is not uncommon for hamsters to mate if given a chance.

If you believe your hamster may be pregnant, I’d recommend having them checked on by a professional. Alternatively, you may be able to observe a change in your hamster’s appearance and habits that may allude to the fact that they’re bearing young.

A hamster’s abdomen will expand in girth as it approaches the end of gestation, and it will eat and drink a lot more than usual. It may also appear as more sluggish and slow.

I advise watching this Youtube video by Christina L. if you are looking to confirm your suspicions on whether or not the hamster is pregnant:

Additionally, if you are not aware of your hamster’s sex, I recommend this quick video by Muna Bruzon:

It will help clarify whether you should be considering if it is pregnant.

Related Hamster articles:


To conclude, while hamsters are commonly inclined to contract illness and infection, most of these issues are simple to spot and understand. By adequately observing the animal’s behavior and appearance, signs of sickness are hard to miss. If any common symptoms occur, it is worthwhile to contact a veterinary specialist to keep your pet definitively healthy.