Are Hamsters and Guinea Pigs the Same? (Plus 7 Differences and 3 Similarities)

Hamsters and guinea pigs are cute little animals. Both are very popular pets, especially for families with kids. And they also look quite similar. If you are not an expert, you might even think that they are the same animal. But are they? Is a hamster a guinea pig or vice versa?

Are hamsters and guinea pigs the same? Hamsters and guinea pigs are not the same animals. They are related, but it is a rather far relationship. Both belong to the order of Rodentia, but they belong to different families. Hamsters belong to the family of Cricetidae, while guinea pigs belong to the family of Caviidae.

Now that we know that hamsters and guinea pigs belong to different animal families, let’s have a look at other differences between the two.

Believe me, there are amazingly many and big differences between both animals. Some of them are really important to know before you decide on one or the other as pets. But we will also point out some similarities that do exist.

We will finally answer the question of whether you can keep hamsters and guinea pigs together.

Differences Between Hamsters and Guinea Pigs


Today, hamsters and guinea pigs live all over the world. But that was not always the case. Originally they come from completely different parts of the world.

Hamsters come originally from Europe, the Middle East, and Asia. This is also reflected in the species’ names. There are Chinese hamsters, Syrian hamsters, European hamsters, Turkish hamster,s and a lot more that contain their origin in their name.

The origin of the guinea pigs lies in South America. As wild animals, they were spread all over the continent. Although there is a Patagonian guinea pig, most do not have a name that indicates their country of origin.


Guinea pigs are vegetarians. Their natural food is grass and hay. But they also enjoy alfalfa a lot! Guinea pigs need to get vitamin C through their food, so it is also necessary to treat them to fresh fruits and vegetables like broccoli, apple, cabbage, carrot, celery, and spinach. Usually, these are included in guinea pig food pellets.

Hamsters on the other hand are omnivores. This means they can eat meat as well as vegetables and fruits. In the wild, they prefer to eat seeds, grass, and insects. Although vegetables are usually included in bought hamster food, it is best to also treat them to fresh fruit and vegetables. One thing to avoid is fruits that contain a lot of citrus.

Weight and Height

Guinea pigs are heavier and larger than hamsters. Adult guinea pigs can weigh between 21 and 42 oz (600 to 1,200 grams) and grow up to 8 or 10 inches (20 to 25 cm).

Hamsters are significantly smaller. They only weigh up to 5 oz (150 grams) and reach 5 to 7 inches (13 to 18 cm) in length.


Hamsters and guinea pigs also differ in reproduction. While guinea pigs breed year-round, most hamsters are seasonal breeders. Only dwarf hamsters also breed all through the year.

One thing hamsters and guinea pigs have in common is that they start to reproduce quite early. It takes only about 4 to 6 weeks for most of them to be able to breed.

Another difference in reproduction is the gestation period. Guinea pigs have a gestation period of 59 to 72 days with an average of 63 to 68 days. Hamsters have a shorter gestation period of only 16 to 23 days.

Both hamsters and guinea pigs can be pregnant up to 5 times a year. In each litter, a guinea pig can have 1 to 6 newborns, while hamsters can have up to 13 newborns per litter.

Social Behavior

Hamsters and guinea pigs differ tremendously in their social behavior. This is one point where they really differ a lot. And it is also something that you should definitely know if you already have or want to buy one of them as a pet.

Hamsters should not be held together. They are solitary animals and don’t tolerate being housed together with other hamsters. This can go as far as attacking or even killing each other!

The exception, of course, is when they want to mate. This is something that even hamsters can not do alone. But if you are seriously thinking about starting to breed hamsters, find out everything you need to know beforehand. A good start might be to talk to other hamster breeders to learn from them.

Guinea pigs on the other hand are very social animals. They need to have company and don’t do well alone. In some countries, it is even illegal to keep guinea pigs alone. This is considered cruelty to animals.

So, if you want to keep guinea pigs as pets, you should always keep in mind that a guinea pig cannot live happily and contentedly by itself. Not even if you spend a lot of time with him.


Another difference between hamsters and guinea pigs is their way of communicating.

Hamsters communicate by using body language and scents. This applies to other hamsters as well as to their owners. They also show how they feel through body language. It is therefore a good idea to learn what signs your hamster might be giving you.

Guinea pigs are rather vocal animals. They use whistles to communicate with each other and with their owners. If they get used to their owner, they might start to whistle when their owner approaches. They might even whistle when you open the door to the closet that contains their food.


Many rodents love to climb. Hamsters are also able to climb, they do this by standing on their hind legs and can then pull themselves up with their front legs.

Guinea pigs do not climb. They are not physically able to do so. With their short limbs, they cannot climb. However, just like hamsters, they can jump.

Similarities of Hamsters and Guinea Pigs


Coprophagy is the technical term for a rather nasty behavior that both hamsters and guinea pigs have. They both eat their feces!

Although this sounds quite disgusting, it is very important for them. They recover previously unabsorbed nutrients from their feces. So if you ever see this behavior in your guinea pig or hamster, don’t be surprised. It is totally normal!


Both hamsters and guinea pigs are nocturnal animals. They prefer to be active at dusk, at night and at dawn.

Being nocturnal offers them some advantages. The most important advantage is certainly that they are better protected from predators in the dark. So it is part of their survival strategy to be nocturnal.


Both guinea pigs and hamsters do not have good eyesight. They are not good at distinguishing colors, and sensing distance visually is not their forte either.

But that’s okay. Both hamsters and guinea pigs are nocturnal animals by nature. Therefore, they do not need color vision as pronounced as, for example, humans.

For them, it is more important that they can recognize contours well even in low light. Therefore, their eyes are simply built differently to provide them with the capabilities they need.

However, their hearing and their sense of smell are pretty good. Hamsters can even hear and communicate in the ultrasonic range.

They also use this ability, for example, to target hamsters of the opposite sex for mating. And they can even pass on information about their age and current state of health via their sounds.

Can I Keep Hamsters and Guinea Pigs Together?

You can keep hamsters and guinea pigs together, but better not in the same cage. There are some things in terms of diseases and also in terms of the behavior of the pets that are against keeping them in the same cage. This would be especially disadvantageous for the guinea pigs.

Hamsters, as well as other pets such as rabbits, can occasionally have respiratory infections. Guinea pigs are particularly susceptible to these diseases and also to other infections.

Therefore, a hamster living in a cage with guinea pigs can infect them. These diseases can have severe courses in guinea pigs.

Therefore, it is better to keep a distance between hamsters and guinea pigs to avoid transmission of these infections.

Another problem is that a hamster could act aggressively and even violently towards the guinea pigs. Although hamsters are smaller than guinea pigs, they have a more dominant behavior.

This more dominant behavior can cause there to be severe problems in the cage, which can also lead to injury or even death of the guinea pigs.

So if you want to keep both hamsters and guinea pigs, do the pets a big favor and keep them in separate cages. Also, don’t put the cages too close to each other to avoid the transmission of pathogens.

Hamsters and Guinea Pigs

We saw that hamsters and guinea pigs are not the same. They are different in many ways and they don’t even belong to the same family. The most noticeable differences are undoubtedly in size and weight, but also their social behavior and their way of communicating are very different.

They also have some things in common. Both are nocturnal animals and therefore their senses also work in a way that is advantageous for a nocturnal lifestyle.

Thus, although they cannot distinguish colors well, they can see quite well even in low light. And their sense of smell and hearing also work very well. These senses are clearly more important in the dark.

But there is one other thing they have in common: both are cute and lovable animals!