What Can Kill a Hamster [13 Reasons]

The thought of losing a beloved hamster is unbearable for any pet parent. Besides death due to old age (usually 2-3 years), there are several environmental and health-related factors that can lead to the death of your tiny fur ball.

Severe illness from untreated disease is one of the major things that kills a hamster. The rodent can also die from several other causes, including serious injury, old age, malnutrition, or eating poisonous foods. Stress, poor hygiene, and a lack of exercise can also kill a hamster.

This article covers the common reasons for death in hamsters in-depth. So keep reading to know the measures you can take to help extend your furry friend’s lifespan.

Things That Can Kill Your Hamster

According to the American Veterinary Medical Association, hamsters are the fourth most popular exotic pets in the United States (behind fish, ferrets, and rabbits).

And while it may sound counterintuitive, their short lifespan is one of the reasons hamsters are a popular pet choice in American households, particularly those with younger children.

The reason for this is simple.

Many parents want their kids to have a “starter” pet that won’t be around when they are off to college.

Hamsters can “suddenly” die due to several other causes besides their short lifespan. Here are some of the most common things that kill a hamster.

What Can Kill a Hamster
A Hamster

1. Untreated Diseases

Although hamsters are somewhat hardy pets, they usually can’t endure being sick for long. Thankfully, not all diseases can quickly kill these animals.

That said, because of their small size, infections and diseases can become serious fast. It’s, therefore, crucial to recognize signs and symptoms of common hamster illnesses early on so you can get your hamster veterinary help on time. Otherwise, there’s a high risk of death.

Examples of deadly hamster diseases include:

  • Wet tail (diarrhea)
  • Cancer of the digestive system
  • Liver disease (biliary and hepatic cysts)
  • Diabetes
  • Kidney problems
  • Pneumonia

Minor infections such as skin and eye problems are generally not fatal and are easy to treat. But watch for symptoms of deadly diseases to ensure your hamster receives treatment as soon as possible.

Read Why Is My Hamster Lying Flat?

2. A poor diet

A poor diet can lead to malnutrition, severely affecting your hamster.

Providing unbalanced nutrients, for instance, can lead to obesity, especially in adult hamsters. An overweight hamster is at a higher risk of developing diabetes, liver problems, and heart trouble. Any of these health conditions can very quickly kill your hamster.

With that in mind, what’s a healthy weight for fully grown hamsters? According to Caring Pets, an adult hamster should ideally weigh:

  • Golden (Syrian) hamster: 5 – 7 ounces (150 – 200 g)
  • Dwarf hamster: 3/4 – 1 3/4 ounces (25 – 50 g)

Also worth noting as far as feeding goes.

Hamsters love fattening foods and will easily overindulge, increasing their risk of obesity. So avoid feeding your hamster fried foods, chocolates, sugary food, and other junk food.

Hamsters also stash food in their adorable little cheek pouches and hide food in their cage. Because of this, make sure you only offer the amount of food needed to meet their nutritional needs and stick to a feeding schedule.

As it turns out, there are several foods your hamster should not consume. Even treats made specifically for hamsters should be provided in moderation, as overindulgence can lead to health problems.

The foods you should avoid are as follows:

  • Meat: Though hamsters in the wild eat insects (and even each other!), domesticated hamsters are omnivores.  A proper diet would include fruits and vegetables and the occasional protein (mealworm or cricket) as a hamster’s digestive system isn’t built to break down meat.
  • Salt: Salty foods are known to strain a hamster’s tiny body and more often than not lead to extreme dehydration if consumed in large amounts.
  • Avocado: Yes, avocado is actually fatal to hamsters if consumed excessively due to the risk of obesity.
  • Celery: Celery is a known choking hazard for hamsters. But if you must feed your hamster celery, then you should cut it into tiny, easily chewable pieces. However, it’s best just to avoid it altogether.
  • Potatoes: Another surprising entry on the list. Potatoes, when baked or mashed, are nutritious. But they’re also filled with starch, which can make your hamster obese if consumed in large amounts.
  • Onions: Hamsters just can’t have any fun, huh? It’s not just hamsters, though. Onions are dangerous for many rodents, including rabbits, guinea pigs, and rats as they’re known to damage the red blood cells.
  • Caffeine: No morning cup of Joe for your hamster! This is because caffeine speeds up the heart rate, and hamsters already have a pretty fast heart rate. Any faster, and they’d have a heart attack.
  • Light green vegetables: These vegetables won’t actually kill your hamster; they’ll just increase the chances of obesity. Light green vegetables tend to provide no nutritional value, and on top of that, they can cause diarrhea.
  • Bitter almonds: While sweet almonds are safe for your hamster to eat, bitter almonds are another matter altogether. This is because bitter almonds have traces of cyanide in them, which is harmful when consumed by hamsters. 
  • Spicy food: For this one to make sense, you’d have to think about the kind of food a hamster would find in the wild, in its natural habitat. Hamsters aren’t initially from America or South America. They are not going to stumble across chili peppers while foraging! They simply aren’t built to digest them and never evolved to.
  • Chocolate: Since hamsters are prone to diabetes, their sugar intake should be monitored closely.  This means avoiding sugary foods and synthetic sugars like chocolates as they’ll end up stressing your hamster’s digestive system. 
  • Other pet food: It might be tempting to give your hamster dog food, cat food, or rat pellets. However, doing so can lead to undesirable outcomes as hamsters have tiny digestive systems that simply can’t handle foods meant for most pets, more specifically cats and dogs.  
  • Dairy: Dairy products are bad for hamsters as they can block their  gastrointestinal tracts, leading to loss of appetite and a wide range of digestive issues. 

As a rule, you should avoid overfeeding your hamster as doing so increases the chances of obesity and other preventable diseases like diabetes. You should also give your hamster foods and treats from trusted brands.

Fortunately, there are several well-established brands in the US that specialize in hamster food and treats. 

Observing a strict meal schedule and investing in enough toys are also great ways to keep your hamster in shape and keep lifestyle illness at bay.

Read What Does Hamster Eat?

3. Prolonged Anorexia

Anorexia in hamsters means a lack of appetite for food. It usually results from a mouth, tooth, or cheek pouch problem.

The condition can make your hamster not eat enough food and drink adequate water. This, in turn, can lead to rapid weight loss, which can be fatal. Make sure to bring your hamster to the vet as quickly as possible if it’s eating little to no food.

4. Feeding Your Hamster Harmful Foods

Certain foods are a complete no-no for hamsters because they can be potentially deadly.

The Hamster Society lists many toxic and unsafe foods to avoid feeding hamsters. Below is a summary of foods to steer clear of:

  • Onions, chives, leeks, and garlic: these foods can cause blood disorders and indigestion in hamsters.
  • Kidney beans: canned and raw kidney beans can be seriously toxic to hamsters.
  • Candy: candies contain empty calories and are full of sugar and chemicals. Continuously feeding your hamster with candy can cause serious health problems such as diabetes.
  • Bitter almonds: the cyanide content in unroasted bitter almonds can be fatal if your hamster consumes too much of it. While your pet rodent is unlikely to eat enough almonds to cause instant death, it’s best to avoid offering them.
  • Eggplants, avocados, and tomato leaves: these foods can easily cause stomach upset and diarrhea in hamsters.
  • Raw potatoes: the arsenic and oxalic acid in raw potatoes are harmful to hamsters.
  • Citric fruits: avoid giving your pet pineapple, lemon, grapefruit, and other types of citrus fruits as they are too acidic for your hamster’s stomach. Citric fruits can cause diarrhea, which can be fatal to the animal.

The best foods to feed your hamster are chow diets (seed mix) and pellets.

You can find high-quality commercial pellets in many pet stores in nearly all the states and cities in the U.S., including New York, Houston, California, and many others.

I recommend Food from The Wild, which you can find on Amazon. This nutritious pellet blend by Kaytee combines sunflower seed, pumpkin seed, peanut, carrot, and rose petal. It contains no added sugar, fillers, or artificial preservatives.

You can supplement pellets and seed mixes with fresh vegetables, such as broccoli, cabbage, spinach, and zucchini.

5. Infections

Due to the nature of their bedding and their habit of stuffing food in their cheeks, hamsters are prone to bacterial infections. Below are examples of infections that hamsters are prone to:

  • Fungal infections: Though fungal infections are rare in hamsters, they can occur when parents don’t clean up the cages well enough. To eliminate the risks of fungal problems, it’s best to remove beddings and disinfect cages regularly.
  • Lymphocytic choriomeningitis virus (LCMV): LCMV affects rodents such as mice, guinea pigs and hamsters and can be transferred to humans. Some of the signs of infection in hamsters include rough coat, appetite loss, lethargicness and hunched posture.
  • Demodex criceti and Demodex aurati infestations: Mite infestation is common in hamsters and usually occurs due to poor hygiene habits. Changing your hamster’s beddings regularly will help reduce mite infestation, especially during old age.

Although not all infections are fatal, they negatively affect your hamster’s quality of life.

The trick to keeping infections at bay is maintaining high standards of hygiene by removing your hamster’s beddings every week and disinfecting the cage before placing new ones.

6. Illnesses

Hamsters are one of the easiest to maintain pets. However, despite their hardiness, these cute tiny furballs are susceptible to a number of genetic, diet, or hygiene-related illnesses.

While most of these illnesses can be treated, they can prove fatal if not treated early enough.

Unfortunately, detecting illnesses in hamsters early enough can prove difficult as they’re rarely active during the day.

Due to this, most pet parents usually discover their hamsters’ illnesses several days or even weeks after they’ve progressed to potentially life-threatening levels.

Read Why Do Hamsters Eat Their Babies

Here are some illnesses that might affect your hamster:

Wet Tail

Wet tail is a common disease that affects almost all hamsters at some point. And although caused by stress, wet tail is highly contagious and can be passed from one hamster to the next.

Aside from the wetness around the tail, wet tail also causes severe dehydration in hamsters. Therefore, if your hamster is drinking more water than usual, and appears to be distressed, chances are he is suffering from wet tail.

Disclaimer, wet tail is a highly fatal disease that requires immediate medical attention. If not treated within 24-48 hours, your hamster could develop serious complications that can lead to death.


Diabetes is actually rare in hamsters but can occur if you give your tiny companion sugary treats without moderation.  Symptoms of diabetes in hamsters include sudden weight loss, excessive drinking, urinating, and lethargy.

A strong ammonia odor will also be present in the hamster’s enclosure. Thankfully, diabetes in hamsters can be prevented by monitoring their sugar intake.

If you suspect that your Hamster has diabetes, it’s best to schedule an appointment with the vet for further tests.  


Pneumonia is not common in hamsters, but it is lethal when they develop it. It typically occurs as the result of infection from different strains of bacteria. Multiple infections are difficult for hamsters to fight off, which eventually leads to premature death.

Pneumonia is another contagious illness in hamsters and yet another reason why hamsters should be housed alone.

If your hamster comes down with pneumonia, it’s crucial to separate him from other hamsters to prevent the spread of the disease.

Symptoms of pneumonia in hamsters include:

  • Difficulty breathing
  • Mucus discharge from the nose
  • Excessive sneezing
  • Fever
  • Lethargy

Pneumonia is, unfortunately, not an illness that can be treated in hamsters. Your best strategy is to prevent pneumonia in your hamster.

If your hamster develops pneumonia anyway, it’s vital to rush him immediately to the vet. Your veterinarian will prescribe antibiotics, but this will be long-term and only serve to treat the symptoms of the illness, not the illness itself.

To be on the safe side and avoid losing your hamster to illnesses, it’s best to examine him regularly and check for any symptoms of illness or change of behavior.

Read How To Empty Hamster Cheek Pouch?

7. Stress

Hamsters are nervous little creatures that are easily prone to stress. Even worse, prolonged stress and anxiety in hamsters is known to lead to depression and ultimately death.

Stress will affect your hamster by weakening his immune system, thereby exposing him to a host of illnesses, among them heart attack and stroke. Here are some things you can do to avoid stressing out your hamster:

  • Permanently house your hamster alone.
  • Allow your hamster enough time to adjust to a new environment.
  • Provide your hamster with many stimulating toys, so it doesn’t become bored.
  • Change your hamster’s diet gradually by adding small amounts of the new food to the old food.

Weather-related stress can also kill a hamster. Therefore, if you live in states with harsh winters like Alaska, Maine, Minnesota, and the Dakotas, it would be best to set up your hamster’s cage in a warm, well-insulated area.

8. Lack of Exercise

Providing a wide cage for your hamster is not enough to keep it healthy. These rodents can run for several miles per night in the wild.

Although small, their habitat and territories in the wild are vast compared to an average human house!

Captive situations don’t offer enough opportunity for hamsters to exercise and stay physically healthy and mentally sharp.

The result?

Boredom, depression, obesity, and stress!

These conditions can negatively affect your hamster’s health and eventually lead to death if you don’t defuse the situation quickly and effectively.

For this reason, a hamster wheel is a must-have in any hamster cage. The exercise device increases the energy expenditure of the rodent, preventing obesity. It also reduces the chances of boredom.

9. Falls and Serious Injuries

In addition to causing stress, putting your hamster at a high height can be dangerous. Your pet rodent can fall and end up with broken limbs, or worse, the fall can be fatal, resulting in instant death.

Deep cuts from falls and blows to vital organs during fights or playtime with other hamsters can also be fatal. Accidentally sitting or stepping on the animal can also kill it on the spot.

You can prevent potentially fatal accidental falls and injuries by hamster-proofing your room or environment before letting the pet out of its cage.

10. Poor Living Conditions

Poor hygiene conditions in the cage can lead to different health problems. Some of which can be deadly. So it’s advisable to maintain a regular cage cleaning schedule.

That said, your pet can still die in a very clean habitat due to other unsafe conditions.

For instance, when you house two or more adult hamsters in one cage, one will likely dominate the other.

As a result, the weaker hamster may constantly eat less and endure bullying and injuries from its dominant cage mate. If this happens, it won’t be long before the chronically stressed hamster dies.

Your best bet is to provide separate cages for your adult hamsters. You can keep young hamsters together until they are about six weeks old. But make sure to house them separately once they’re older to avoid dominance aggression.

11. Fear

Fear, the mother of stress, can absolutely kill a hamster. Because hamsters are naturally anxious and prone to stress-induced illnesses, it only follows that fear would have such a massive impact on their nervous systems.

Hamsters are also susceptible to heart attacks and several cardiovascular diseases. If you live with unsocialized dogs and cats or excessively loud roommates, then your hamster could be exposed to repeated incidents of fear.

If your hamster doesn’t feel safe in his immediate environment,  then he’ll almost certainly live in a constant state of fear.

Failure to make the home environment accommodative for your hamster will only increase the chances of stress and depression due to fear, and you don’t want that!

Read Why Does My Hamster Stink?

12. Other Hamsters

Sometimes the reason for death is other hamsters. Hamsters are solitary creatures by nature. Their evolution as prey was characterized by their need to store and hide food, which in turn led to competition between hamsters. Over time hamsters became less pack animals and more lone wolves.

For this reason, hamsters should always be housed alone. Otherwise, they might fight over food, toys, bedding areas, and hiding spaces, which can lead to preventable fatalities.

A hamster that is bitten in the face, for example, could develop an infection that leads to a loss of appetite. If left untreated the situation can worsen and eventually lead to death.

Hamsters also eat their young in isolated cases. This usually happens if the mother hamster isn’t being fed enough or if the litter size is too big for her to handle. As a coping mechanism, a nursing mother might elect to eat her weakest pup if she’s hungry.

 A mother hamster can also kill a sickly baby hamster or attack some members of the litter if she notices a change in scent (if a human or other animal touched the babies).

As a good rule of thumb, you should alter a nursing hamster’s feeding and drinking patterns to suit her unique needs. Your vet can give you useful tips on how to make the nursing environment accommodative to the mother and her pups.

what will kill a hamster
what will kill a hamster

13. Old Age

Lastly, old age can cause death in hamsters. This cause of death is natural but may seem too sudden in hamsters because of their relatively short lifespan.

It is not unusual for hamsters to become “very old” at only 18 months. At this age, they require a little extra love and care, which can extend their lives a bit.

However, hamsters do not typically live longer than 18 to 36 months.

Do Hamsters Die Suddenly?

Now that you know the common causes of hamster deaths and how to prevent them, let’s answer one final question.

Can a hamster die without warning?

It’s common for new owners to think of their hamster’s death as sudden. And if the animal didn’t die of old age or any fatal injury, this can certainly be the case.

But …,

Hamsters do not die suddenly, particularly those that die from illnesses. A sick hamster always shows signs of being ill. It’s only that most hamster owners do not pay close attention to these warning signs, which makes the death of their pet appear sudden and unexplained.

So how come many people miss the telltale signs of sickness in hamsters?

Well, like many other prey animals, hamsters have a self-preservation instinct. That means they will do anything to protect themselves from predators or threats, including playing dead or pretending to be healthy when sick.

Therefore, your pet rodent will naturally want to hide its illness and carry on normal activities as if nothing is wrong. The hamster behaves like this because it doesn’t want a predator to take undue advantage of its “weakness.”

And while captive situations do not require this kind of pretense, domesticated hamsters can’t help their instincts to survive.

What does this mean to you as a hamster owner?

Your pet hamster can “drop dead all of a sudden” if you don’t pay close attention to subtle changes in its behavior.

In many cases, a hamster’s condition is already at a severe stage before it becomes obvious.

For this reason, you must familiarize yourself with your hamster’s normal behavior so that you can quickly notice when something is off, even if the rodent tries to hide it.

Here are a few tips on how to examine your hamster:

  • Gently run your hand over your pet’s body when you cuddle it. Doing this will help you notice if there are any unusual lumps.
  • Check the eyes and nose for discharges. A runny nose and discharges from the eyes can indicate an infection.
  • Regularly weigh your hamster. You can use a kitchen scale to determine whether your pet is losing weight, becoming obese, or maintaining a healthy weight. Do this at least once or twice a month.

Ensure to consult a veterinarian at the first sign of ill health. Sick hamsters can quickly go from bad to worse, so it is in your pet’s best interest to act as soon as you notice something’s wrong.

Related Hamster articles:


As established throughout the article, hamsters are prone to several illnesses that can shorten their lifespan.

The good news, however, is that most causes of death in hamsters are avoidable, which means you can prolong your furry companion’s life by observing the right practices.

This means maintaining proper cage hygiene and ensuring your hamster is housed in a calm, highly conducive environment.  Observing a balanced diet and scheduling routine checkups with a trusted vet will also keep your hamster healthy and avoid premature death.