So. One day you're minding your own business and suddenly, without warning, you are responsible for the well-being of a lagomorph! You have no idea what to do! Panic!
No. Don't panic. E2 has you covered. This node tells you what you need to know in a pinch (and indeed out of one). This is not a comprehensive guide - consult your friendly vet first and foremost.
Okay. First off, pellets are the staple food. Vegetables are healthy, but not a dietary mainstay as too many will give them diarrhea. In other words, veggies are to bunnies rather as fruit is to humans. Raisins make especially good one-off treats, but again too many and the bunny gets the runs. Treat these like bunny candy.
Secondly, rabbits are latrine animals. This means they will pick a spot and thereafter that is their toilet. Your best bet is just to hope it picks a convenient one, and put the litterbox there - problem solved! Rabbit poo is very tractable and not messy at all; it's hard. You may have heard that rabbits eat their poo to redigest it - they do, but the poo they eat is very soft and sticky, and you should be glad they eat it most of the time because it's a lot nastier than the ball bearing-like poo you'll normally deal with. Rabbit urine on the other hand is thick and dark orangey, not so different from cat piss. It smells and it stains. Fortunately all of it will typically go in the litterbox once they've chosen a spot. Caveat: If it's a guy rabbit he will mark territory unless he's been neutered, which you'll probably want him to be. I don't know what effect using "cat litter" instead of "rabbit litter" would be, and I would not be inclined to experiment with this - litter choice can have a dramatic, frequently life-or-death impact on health. Many bunnies, particularly the larger ones, are prone to respiratory ailments, so avoid anything dusty. Wood shavings are also said to be harmful. Again, I cannot over stress the importance of consulting your vet.
Thirdly, YOU NEED TO RABBIT-PROOF YOUR HOME. This is like baby-proofing, but harder. Rabbits are smarter, more agile, and more mischievous than humans under the age of 2 or so (after that our ridiculously oversized primate brain begins to throw the balance). Apart from their talent for finding ways of getting into trouble, the main thing you have to be aware of is that they nibble constantly. It's an instinct to help them keep their teeth sharp and trim. You can try giving them a nice stick, but don't be surprised if they ignore it and head straight for the delicious mahogany desk.
RULE 1: "Anything chewable needs to be kept away!"
They especially like to nibble electrical wires. Amazingly, I've never known one to actually get hurt doing this, but it's obviously still to be avoided as you're liable to get zapped yourself if you touch a frayed wire. Lamp cord is the worst because it's the tastiest and it's thin so they get through it quickly. Important documents deserve special consideration, as rabbits treat paper like you treat... well, like you would treat something delicious that lay everywhere. Sorry, there isn't really a good analogy.
RULE 2: "Everything is chewable."
In terms of how to rabbit-proof, well you'll have to use the inventiveness granted you by that ridiculously oversized primate brain I mentioned. (Funny story - we once sprayed a wooden baby gate with the hottest hot sauce we could find - so ferocious it irritated skin - in an attempt to stop our rabbit of the time ("Rupert") from nibbling through it. He merely liked the taste even more.) Don't worry though - as time goes on, you will come to regard bite marks as natural aesthetic features of furniture, and the utility of being able to effectively date a piece of paper by how much of it is left cannot be understated.
You probably want to confine the rabbit to a particular room until it can get comfortable in its new home. This also helpfully gives you time to rabbit-proof, and the opportunity to funnel your furry friend into picking a toilet spot in that room.
Rabbits have very strong back legs, stronger than you think. They are used for both defense (running) and attack (kicking). Do not underestimate them. Rabbits can jump as high as cats, albeit less gracefully. Bear this in mind when rabbit-proofing. They can also outrun you in all circumstances. Don't let them outside unless you
1. Keep them on a tether (enclosed spaces are not good enough, as they can jump over or dig under most obstacles)
2. Watch them at all times (beware dogs, hawks, and bids for the open meadows!)
3. Don't mind having big holes dug in your lawn.
Generally, it's easier and safer not to bother and just keep them indoors.
Holding rabbits: don't. The smaller ones may tolerate it, especially if they've been brought up with it, but they really don't like it; it triggers the "being carried off by a hawk" instinct, which in turn can trigger the "struggle and kick like a mule" instinct. This is nearly as hard wired as a gag reflex - I've never known a larger rabbit to not struggle when picked up no matter how trusted the picker-upper. Remember those back legs? Yeah, they will mess up your forearm like nobody's business if you're not careful. Worse still, those incredibly powerful muscles are braced against the pelvis and spine and designed to work against a solid surface; wildly kicking into empty air can break a rabbit's back. If you absolutely have to carry a rabbit, cradle them like a baby (figuratively speaking - for the love of all that is holy don't hold them belly-up) and gently but firmly tuck their back legs solidly against you under your arm, so they can't kick effectively.
Rabbits have an interesting and endearing psychology. They are herd animals, prey animals, and herbivores, and thus they are probably most similar to horses and deer. They don't like chasing or fetching games - such things are the trappings of hunters. Digging, seeking, uncovering and finding games are more their style. In the wild, they normally live underground in warrens, and so are really turned on by cozy dark hidey holes. "Blanket fort" is exactly the kind of game they love, and a maze of cardboard boxes with holes cut in them will delight them (for about 5 seconds until they realise that cardboard is edible, wherupon it will delight them even more). If you really want to go all out, head down to the hardware store and buy some large piping (such as ventilation ducting). At Christmas you may enjoy giving them a present of raisins hidden in a hollowed out carrot (corkscrews are ideal for hollowing out carrots), all wrapped in wrapping paper - they understand the concept immediately, though they may be confused as to which part is supposed to be the edible part, and they may neglect the carrot once they find the raisins!
They are gregarious creatures, and will get lonely if neglected. You can give them a cage to sleep or rest in (put something on the floor so it's comfy and cover it with a towel or blanket so it feels hidey-holey) but keep it seperate from the litter box and don't lock them in it, except possibly at night. If you have any other pets, be exceedingly careful about how you introduce them - dogs are pack animals and will accept basically any crittur into the pack given time, but will initially see your new family member as something to be chased and eaten. Cats are psychotic bastards and cannot ever be trusted, but they do understand the meaning of a good arse-kicking which with a bit of luck the rabbit will administer if harassed too much. Consult your vet about possible disease vectors - speaking personally, both times I've had a rabbit and a cat simultaneously the rabbit has mysteriously and precipitously dropped dead at a relatively young age, and not from any fight either. This doesn't happen to everyone but it was enough to make me not want to keep cats and rabbits together.
Rabbits are crepuscular. Apart from being a useful word if you want to swear but are in polite company, that means they are most active at dawn and dusk. Sometimes you may see your rabbit dashing wildly about the house at great speed and doing jumps and twists in midair. Don't worry, this isn't a panic attack or a seizure, it's simply an exuberant form of play. Horses do it too.
Once a rabbit comes to trust you very well, they may even initiate cuddling sessions. There are few more rewarding experiences than lying on the floor reading a book or magazine and hearing the thump of approaching rabbit feet, followed by the soft warm feeling of a rabbit flopping against your side.
That should be enough to get you started. Soon you will have a new friend and will wonder how you ever managed in your old, rabbit-free life. Happy Bunnying!
p.s. 90% of visitors to your home will think it funny to make "jokes" regarding the edibility of bunnies. TAKE. NO. SHIT.
p.p.s. this writeup dedicated to Roger and Zephronias