Return to Entertaining Norwegians start-page
Rats can get on OK with much larger animals such as cats, dogs and rabbits provided these have been brought up with rats and know not to attack them. Indeed, I know of two cases where rats have palled up with rabbits to the point of sharing a cage with them; and I myself have successfully introduced an elderly buck rat whose brother had just died to a boar guinea-pig whose mate had died, and they settled down together with little friction.
However, some rats, especially does, are terrible teases, and may persecute another animal for fun even if they don't mean it any real harm. Many, for example, will chase a guinea-pig round and round the room for the pleasure of hearing it make funny noises; and some will swarm up a cat's legs or tail.
By the same token some young cats may be a bit risky with rats even if they have accepted the rats as other small, funny-looking cats rather than as mobile meals - because some young cats think that the most appropriate thing to do to another cat is to wrap their arms round it and kick it, purely in a spirit of fun.
Also remember you will probably have to put other animals' food out of reach while your rats are out. Not only will rats swipe cat and dog-food: they also wade through it, and some cats and dogs don't appreciate their dinner tasting of feet.
The large animal rats most commonly get on well with is Homo sapiens. They vary considerably in their sociability, and some are never very keen on humans - while some rats, especially bucks, may love one human to distraction but dislike everybody else. On the whole, however, the fancy rat is the most universally friendly of all cage pets. Many rats really like humans immensely, and nearly all are at least amiably tolerant of them: they like to sit on humans; climb on humans; groom humans; be petted by humans; burrow up human sleeves and into human armpits; investigate the contents of human ears and nostrils and sample whatever humans may be eating.
Some rats, even if they like humans, don't respond to them as other rats: but many do, and will groom you exactly as they would another rat (which feels like being scraped with a very small, blunt razor: but put up with it as long as you can). Even quite hostile rats will usually groom you back if you groom (bath, brush etc.) them.
Even rats who aren't all that keen on humans may still respond to them socially. I was once holding, or trying to hold, a very large, stroppy buck called Eric Bloodaxe: as he thrashed and yelled I kissed him and he immediately stopped trying to get away, turned and gave me a delicate little groom - and then went right back to wriggling and shouting. If he'd said it in English he couldn't have expressed himself more clearly: "OK, I love you too but let go of me."
Be cautious about introducing rats to smaller animals. Many rats will kill and eat smaller rodents such as mice and gerbils, and a very few will kill larger animals such as guinea pigs.
I do know of one case where somebody kept some very amiable Himalayan buck rats in the same cage with mice, and the mice used the rats as furry duvets. But some buck rats are absolutely infuriated by the smell of a male mouse, which seems to have a sort of super-male, challenging quality: and some male mice are so hormone-happy they really will challenge a buck rat to a fight. So although it's not impossible to introduce rats and mice successfully, until you've tried it and seen them getting on together there's always going to be a risk the mouse will get eaten: indeed some rats not only kill mice but store their corpses in neat piles for future consumption. On the whole, on average, a mouse is probably safer with a cat than with a rat. Rats strike faster, and they don't waste time playing.
Experts on jirds (small-rat-sized, mega cute-looking giant gerbils who mostly really hate each other) recommend keeping jirds with rats rather than other jirds. It is probably best if the rats have grown up with jirds from a very early age, however. I had three jirds who got on fine with most of my rats: they used to squabble with some of the does, but the rat-does definitely treated the jird-does as other rats rather than as prey. But one aggressive old buck rat got at them and killed two of them before I could stop him.
Rats who don't view other small(er) animals as food may see them as rivals to be fought and driven away, and vice versa - e.g. a male guinea pig may attack a male rat.
If rats do get on well with another species they may become sexually attracted to it. I once had a very small, nutty doe called Badger (the same one portrayed in the clip at the top of this page) who had a thing for cats. She was absolutely fixated on them and would chase them round and round the room. Our old long-haired cat Plush was calm enough to put up with her without running so she used to stick her head in his mouth and pick his teeth, and I once saw her mount the tuft on the end of his tail.
Indeed many rats like to rummage about on cats. There is supposed to be a parasitic disease which causes rats to be attracted to cats in order to infest the cat when the rat is eaten: but if so I'm pretty sure it is merely disinhibiting a behaviour which is already present but normally suppressed by fear/common-sense. The attraction cats have for rats seems to be an extension of the rat's grooming and nesting behaviour: they just love all that thick fur, either to groom or to yank out in mouthfuls to add to their nest. It's equivalent to the passion some rats have for chewing human toe-nails: the presence of so much horn, or fur, seems to overstimulate them and send them into a paroxysm of grooming. I have heard it said that rats will even chew horses' hooves and elephants' toenails.
Some rats, of course, pull the cat's fur, or dart out and bite your toe, just because they enjoy getting a reaction.