Rats and mice both make awesome pets. However, although they are closely related species, they offer different pet-owning experiences. Here are some things to think about in choosing which is the right pet for you.
Table of Contents
Handling and bonding
Rats are very much people pets. They often develop strong bonds with their owners, and actively want to spend time in their company, playing, cuddling, burrowing in clothes, or using their human as a climbing frame.
Pet mice can and should be handled, but they are a bit more self-sufficient. Rats need time out their cage to play with their owners every day; generally for at least an hour. Mine certainly make it known if they think their cage doors aren’t spending enough time open!
Mice on the other hand don’t mind if their owner misses a day or even several days – their focus is more on playing in their cage, which is why it is vital to have a cage set-up with lots of enrichment.
Rats are also easier to handle physically. Both species need to be handled with care and respect, but rats are bigger and more robust, and if tame are likely to move more slowly.
So, if you want pets who will be your best buddies, rats have the edge, whereas if you prefer a more independent and low maintenance friend, mice might be your thing.
All pet rodents need a well furnished cage to live in. In all cases, the cages need to be right for the species, and be set up with plenty of things for the animals to do. Rats and mice are both quite bright for their size, so neither will thrive in an empty tank, or a cage that is too small for them to express natural behaviours.
As you might expect, rats do need bigger cages than mice, but the difference isn’t as large as you might think. That’s because the space needed is dictated by behaviour rather than body size, and mice are very active in their cage. The minimum size of cage I’d use for a pair of rats is around 80 x 50 x 80 cm (31 x 20 x 31 in). A pair of mice can be housed in a lower cage, which is easier to stack on a dresser, but a cage footprint of 80 x 50 cm (31 x 20 in) is still ideal. That’s because it gives room for lots of substrate for digging in, which is an important natural behaviour.
One of the big issues in finding a suitable mouse cage is making sure the bar spacing is small enough (0.5 – 1 cm / 0.2 – 0.4 inch – depending on the build of the mice), and the cage is of good quality (a snapped bar means an escaped mouse). The cheap small “mouse” cages you might see in pet shops aren’t usually big enough, and won’t last.
A smaller cage means smaller furniture, but not less enrichment. Mice and rats both need things to play with and explore in their cages – houses, tubes, ropes, branches, wheels and so on. However, mice are quite easy to make home-made toys for, with things like toilet roll inners, cereal boxes making ideal nests and burrows.
Both rats and mice are relatively low expense pets compared to something like a dog, but they do both come with costs any owner needs to meet. These include buying the cage and furniture, food, litter, and of course the animals themselves. It also means vets bills.
Overall, mice are the cheaper pet. The things you need to buy for them are generally smaller and therefore lower priced, and of course being much smaller animals they eat less food at a time.
Any animal, including mice, should be taken to the vet if they develop health problems. However, overall, mice are very good at hiding medical problems, and are less well suited to interventions such as surgery (although I once asked my vet what the smallest thing he’d operated on was and he said “the sheath of a mouse’s penis”). They are more likely to develop acute problems and harder to medicate, so a mouse owner may have to make more decisions about euthanasia where in rats the illness could be treated.
Rats can be very prone to chronic medical problems that require intervention from a vet. Much of this comes down to how well the animals have been bred, but it isn’t unusual for a rat owner to need to consult a vet about problems such as chest infections and mammary tumours. Vets’ bills can be a significant, and unexpected, expense for rat owners.
Neither rats or mice are suitable pets if the owner doesn’t have enough income to support their needs.
Smell and cleanliness
To be honest, most issues of smell and cleanliness in caged animals are not about the species, but about their care – what they are bedded on, whether they have enough space, and how often they are cleaned out. Rats and mice do have some differences in smell, but neither should be a problem in the house if they are properly cared for.
Mice tend to have a more distinctive smell than rats. That’s down to biology – mice, especially the males, have a natural musky scent that in the wild they use to mark territory and trails. You’ll usually find rat owners claiming mice smell more and vice versa. With any pet it’s a good idea to visit an existing owner to see how you personally feel about things like smell.
Sadly, neither rats nor mice live for very long.
The average lifespan for pet mice is 1-2 years while for rats it is closer to 2-3. The difference isn’t huge, but it may be worth taking into account if you know you’ll have other commitments in your life longer term.
Aggressiveness and skittishness
Pet rats and pet mice should be tame and non-aggressive if they have been responsibly bred, as their temperaments will be something a good breeder selects for.
In both species, males may show hormonal aggression, to their owner or their cage mates (usually around 6 months in rats, and 4-5 months in mice). This sometimes fades away as they grow up or can be cured by neutering. Both species can be castrated, while rats can also have a hormonal implant to reduce aggression (I wouldn’t personally rely on it to prevent pregnancies!).
Mice and rats should be kept in single species, single sex pairs or groups. They are naturally social animals who benefit hugely from the companionship of their own kind. If a male rat is aggressive to other rats then neutering is, in my view, the kindest option.
You will sometimes see people say that adult male mice have to be kept alone. This is very much down to the individual mouse and the line they come from. The key is for mice to be introduced young, before they become hormonal. Other options include castrating a male and introducing him to a female or female / castrated male group, or to a good tempered male.
I’ve had very few problems introducing male or female unrelated rats to same sex groups (although I frequently neuter the males for other reasons, which of course makes it easier). The key is doing the introduction carefully.
So, which are better – pet rats or mice? Neither rats nor mice are the “better” pet – it all comes down to what pet species will suit your lifestyle, budget, and how you prefer interacting with your animals.