What is the difference between a hamster and a guinea pig?

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If we had a pound for every time we heard the phrase "How are your hamsters?" or "Look Isabelle, it's a hamster circus!" we'd be very rich indeed! It's frankly astounding how many people confuse the two. Yes, they are both small furries with two eyes and a nose, but you wouldn't call a dog a cat, so why do people do it?!

Just before Christmas we got some fabulous coverage in the Sunday Times which resulted in the article we were featured in being talked about on BBC Breakfast News. In it, the guest analyst discussed the latest trends in pet products, with consumers looking for higher quality, luxury products for their pampered pets. He then made reference to our Cavy Cannonball™ - Tilting Tunnel (featured on the front cover of the Sunday Times Home supplement) and called it a "hamster cannon"(!).  Well, we just had to laugh, here we were again, confronted by another case of mistaken identity.

 So why does it happen, is it that difficult to tell the difference?

Could it just be ignorance? Admittedly, a baby guinea pig does look fairly similar to a hamster (when you squint your eyes while chopping onions) but surely there are a few telltale signs that give us a clue...



1. They are furry. Can't argue that one (unless it's hairless breed like a Skinny Pig!)

2. They have little round eyes on the side of their heads. (Yep, both the same on this score)

3. They have four legs. OK, got to state the obvious now, but yes, they do have the same number of legs. That said, both species use their legs differently; piggies tend to stay on all fours while hamsters are more likely to sit up on their back feet and use their front paws to hold food or climb.

4. They are related (but it's a fairly distant relationship). Both guinea pigs and hamsters belong to the order of Rodentia - so they are both rodents. But they don't share the same family; guinea pigs are members of the Caviidae (or Cavi) family while hamsters are members of the Cricetidae family.

5. They have very similar teeth. Two large incisors top and bottom and then a row of premolars and molars for grinding down food. These teeth are continuously growing hence why it is important that your small furries get the right nutrition and forage to wear them down.


1. They grow to a completely different size! Typically a fully gown guinea pig will measure somewhere between 20-30cm while a hamster will only reach around 5-15cm*


*there are obviously different breeds of hamster and their sizes can vary, but this is based on two of the more common breeds found in pet shops; Syrian hamsters and Dwarf hamsters.

2. A guinea pigs life expectancy is considerably longer! You can expect your guinea pig to live 5-8 years if it stays fit and healthy whereas a hamster typically lives 2-3 years.

3. Guinea pigs are herbivorous while hamsters are omnivorous! Put simply, guinea pigs are vegans (kind of!!) and will not eat meat, although it's by necessity rather than choice! A hamster can eat 'meat' (or put scientifically; obtain chemical energy and nutrients from materials originating from animal origin) although it is more likely to be in the form of insects rather than a full-on roast dinner!

4. Their offspring are very different! Guinea pigs give birth to pups that are born with hair, a full set of teeth, eyes wide open and the ability to run around. A litter is typically around 2-4 pups. A hamster’s offspring will be born without sight and hair and their litters can be as large as 20 (although typically more like 6-12 pups).

5. Guinea pigs are a lot more sociable! We're not just being nasty to hamsters here, but it is a well-known fact that (in general) guinea pigs enjoy interacting with one another and indeed, other animals (including humans!). Yes, they are small furry socialites! In fact, this need for constant connections is so strong, guinea pigs can really suffer in isolation, become depressed and even die from loneliness. In contrast, hamsters aren’t fussed about hanging out with one another and can actually become very aggressive in each other’s company, particularly when there is food about!

6. Guinea pigs are not good climbers! While you may catch your guinea pig scaling over a low-sided play pen or ascending a staircase, they are not good climbers (in the truest sense of the word). What I mean by that is, they don’t pull themselves us using their paws. Instead, they tend to jump (and are actually rather good at it!). In contrast, hamsters love to climb and often scale up the bars in their cage.

7. Guinea pigs cannot run in a wheel! Let’s be very clear here; guinea pigs CANNOT run in a wheel, it’s physically impossible for them and quite dangerous. While our hamster friends will happily run all day in a wheel, a guinea pig’s spine is simply not built for it and trying to use one will cause them pain or even permanent damage to their back.

8. Guinea pigs cannot use exercise balls! And here’s another health warning; guinea pigs should absolutely NOT be using exercise balls. Again, it requires backward arching of the spine, something rats, mice and hamsters have no problem with, but guinea pigs are simply not physically built for.

9. Guinea pigs do not carry food in their cheeks! As much as they’d probably like to(!), guinea pigs do not have the ability to carry food around with them, this is a trait of hamsters. While it may seem amusing, it’s simply a hamsters way of food hoarding. In contrast, a guinea pig tends to wolf their food down in one go and then wheek for more!

10. Guinea pigs are not nocturnal! It’s often the case that small prey animals (such as rodents) choose to spend most of their waking hours in the dark. This is a basic defence mechanism against predators, who will find them harder to spot than in daylight. This is certainly true of hamsters, who will do most of their scurrying about and eating at night. Guinea pigs on the other hand tend to just take a nap as and when they feel like it! This is a bit of an oddity, but it has been suggested that this is a direct result of their prolonged domestication. They just don’t feel threatened like they did in the wild! So rather than sleeping at night or during the day, guinea pigs are actually masters of the power nap and (with frequent short sleeps) can be awake for as long as 20hrs within a 24hr period.


Clearly a guinea pig is nothing like a hamster and there are a lot of differences between the species (listed above), so the fact that people muddle them up is somewhat perplexing. It just seems a bit ignorant and lazy to me. So the next time someone drops the 'H' bomb on you and calls your guinea pig a hamster, please point them in the direction of this blog for some light reading or memorise the content for a smug retort!