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Why Do Hamsters Kill Each Other? 6 Common Reasons & What to Do

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By Nicole Cosgrove

two hamsters inside cage

Tiny, fuzzy, and cute, in the right hands, hamsters make excellent companions. They are independent, not at all clingy, and like to get cuddly. And once these little buds warm up to you, they often become incredibly affectionate. Hamsters don’t feel the same way about their own kind, though, and tend to be extremely aggressive and territorial.

They’re used to fighting each other to death for territory. In other cases, mothers eat newborns to “recharge their batteries” and stay alive. Unfortunately, this doesn’t only apply to wild hamsters: their primal, barbaric instincts don’t go away in captivity. So, why does this happen, exactly? And how do you put a stop to this? Time to find out!


The 6 Reasons Why Hamsters Kill Each Other

1. It’s All About Turf Wars

Hamsters are not at all friendly or tolerant toward their brothers and sisters. Also, in contrast to most species, the females are more aggressive than the males. They fight fellow hamsters for territory and only stop once they accept defeat and leave (or when that other hamster simply can’t fight anymore). This is why it’s NOT recommended to keep two hamsters in the same cage.

No matter how spacious it might be, these little cannibals will still start a skirmish. And the chances of you finding one of the pets dead in the corner are disturbingly high.

cute female Winter White Dwarf Hamster scratching and grooming its fur
Image Credit: Victor FlowerFly, Shutterstock

2. Lack of Food and Shelter Are to Blame

Like most rodents, hamsters have lots of babies, and they fight each other for food and water. Or when there aren’t enough safe and cozy burrows, they compete for survival. Overcrowding is a huge problem for these creatures. So, while they won’t necessarily eat each other, the injuries are often severe enough to kill a hamster or make it easy prey.

3. Stress Also Plays a Big Role in the Killings

The wilderness is not a welcoming place for hamsters. Their claws and teeth are too weak to fight bigger, stronger animals. Hamsters are hunted by a wide range of predators, including buzzards, foxes, eagles, and badgers. Naturally, that leads to a buildup of stress and anxiety. And in contrast to dogs, sheep, and elephants, hamsters are not pack animals.

So, when they’re surrounded by a bunch of other hamsters, that might lead to cannibalism. Also, these pets only enjoy life in captivity when they have a large enough cage at their disposal. There’s a condition known as “cage rage”; it makes these buds overly aggressive and leads to random biting and urinating.

  • For dwarf hamsters, 640 square inches of real estate is the bare minimum.
  • For larger species, aim for at least 800 square inches or more.
roborovski dwarf hamster
Image Credit: ITSUKY, Shutterstock

4. The Mother Needs Nutrition to Survive

Female hamsters become mothers at a very young age, and sometimes, they panic and kill their babies. Or it could be that the mom is running low on vitamins and has to eat her offspring to survive. This mostly applies to hamsters that don’t get vital nutrients like vitamin B3. In other cases, they eat the young to “cut the numbers” and make sure there’s enough food or water for everyone.

Lastly, mothers may devour baby hamsters to return to estrus and produce a healthier group (litter). Males eat the young as a source of nutrition too, by the way.

5. Males Get Rid of Unrelated Pups (Baby Hamsters)

Infanticide is rather common in the animal kingdom. Bears, lions, and horses are the most prominent baby-killing species, but rodents do that as well. The list includes squirrels, mice, and, sadly, hamsters. But what’s the point of this—why do the males kill the young? This is done to make the female fertile again and produce their own offspring.

Also, they don’t want the babies of another male to grow into adults. From their point of view, there’s absolutely no reason to feed or protect cubs that aren’t biologically related to them. So, while it might not always be easy to tell exactly why hamsters kill their babies, it could very well be dictated by this ancient reproductive strategy.

a mother hamster with her newborn babies
Image Credit: sanchai buasong, Shutterstock

6. It Could be That the Pups Are Sick

This is another widespread phenomenon in the wilderness. Mothers and fathers kill and eat infected or diseased babies to prevent the sickness from spreading. We often see female cats do this to their young. You might think that the feline is doing something wrong, but it’s actually trying to save the rest of its litter. The same goes for hamsters and many other domesticated animals.


How Do You Stop Hamster Cannibalism?

First, see that the mom has a large enough cage and can deliver her babies in a peaceful, stress-free area. Moving the mother to a different cage when she’s about to deliver is a bad idea. She may panic, think that she can’t handle the pressure of being a mother, and devour the kiddos before long. Instead, provide her and the newborns with plenty of food and water.

Treating the female with meat and apples can help as well. Next, make sure the males are nowhere near the litter when the babies are born. You shouldn’t bother the pups, either (give them +/- two weeks of alone time; your scent might confuse the mom). Don’t clean the cage or change the bedding during this time. However, if you see stillborn hamsters, be quick to remove them from the cage.

Can You Make Hamsters Co-Exist Peacefully? A Detailed Guide

  • Adopt the least aggressive species. Dwarf (Russian and Roborovski) and Campbell’s hamsters are friendly and often get along just fine. In contrast, Syrian and Chinese hamsters are alarmingly aggressive, and no amount of snacks, petting, or verbal encouragement will make them tolerate another furry critter in their cage. So, make sure you’re not bringing home a feisty pet!
  • Socialize the pets at a young age. Early socialization is an effective technique for making animals co-exist and (with luck) warm up to each other. As mentioned, Dwarf hamsters don’t necessarily mind being a part of a bigger family in captivity because, in the wilderness, they’re quite social and easygoing. Raise them together, and they might just become friends!
  • Separate the boys from the girls. In contrast to dogs and other four-legged buds, hamsters tend to be more aggressive with the opposite sex. That means you shouldn’t keep a male and a female in the same cage, as that might lead to a quarrel (or new babies). Same-sex hamsters will still fight, though. Can’t figure out the pet’s sex? Talk to a veterinarian for guidance.
  • Don’t put two hamsters in the same cage. Want to play it safe? Then instead of buying one large cage, invest in two smaller ones and let the pets enjoy their freedom. With that, put their cages in the same room so that the little champs can get used to one another without getting violent. Next, try putting them in a new cage together and see what happens.
  • Have two sets of bowls and wheels. By now, we’ve learned that hamsters don’t like to share. So, make sure each rodent has its own bowls for food and water, bed, wheel, and toys. Ideally, the cage should also have two separate entrances that each hamster can use without crossing paths with the other guy. Lastly, treat the pets the same way.
  • Let the dominant hamster do its thing. If you’re new to hamsters, watching them play and fight can be rather disturbing. However, squabbling is normal behavior for these critters. More than that, the dominant pet will jump on top of the submissive one until it accepts defeat. If there’s no violence involved (biting, chasing, and cornering), let things play out.

Taking Care of a Pet Hamster: What You Need to Know

Hamsters are often categorized as “starter pets” because of their miniature size, but taking care of these rodents does take time and effort. The key here is to be gentle and patient and socialize the pet while it’s still a pup. A properly raised hamster can be joyful, affectionate, and easy to maintain. Future parents will also be pleased to learn that hamsters are independent and clean critters.

On the downside, these gnawers are officially recognized as the most aggressive pocket pets. When stressed (like if you startle them), they often resort to biting. That’s why it’s NOT recommended to let children play with them. Always provide supervision and make sure the kids know how to handle such a pet.

Here are some more important things to keep in mind:
  • Hamsters are nocturnal creatures but can also be active during the day.
  • On average, they live for 18–36 months. The larger species live longer.
  • They are gifted chewers and can make short work of bedding in the cage.
  • A hamster’s bite is not that painful but can still hurt if the pet is stressed.
  • Seeds are not the best food for hamsters, as it makes them fat.
  • Pellets combined with some veggies and occasional fruit is the perfect diet.
  • These rodents are prone to overheating and prefer to live in cooler areas.
  • Have the hamster checked by a veterinarian once you adopt it.



Hamsters are independent, fun, and adorable. To a first-time owner, they may seem like the sweetest, most peaceful creatures on the planet. However, before adopting a hamster, you should know that these gnawers can be hostile toward their siblings and don’t like to share cages, food, or toys. Furthermore, hamsters have cannibalistic tendencies!

For example, the Syrian and Chinese species sometimes eat each other to assert dominance, take back precious territory, or thin out the herd. Today, we talked about the causes and meanings behind these unsettling behaviors and ways to minimize the violence. Follow these simple yet important rules, and you should be able to shape your pet hamsters into exemplary rodent citizens!

Featured Image Credit: HelloRF Zcool, Shutterstock

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