With a little time, you can turn a pair of rabbits into lifetime bunny buddies.
Step 1: First, make sure both rabbits are spayed or neutered, which will ensure they are less aggressive, and you don't end up with a whole bunny brood. Then, be patient. It may take several weeks of daily "bonding sessions" before the rabbits take to each other.
TIP: In general, it's easiest to bond a neutered male rabbit and a spayed female, but same-sex, "fixed" rabbits can also learn to be friends.
Step 2: Put the two rabbits' cages or pens next to each other. The bunnies should be close enough to sit near each other, but not so close that they can nip each other through the bars.
TIP: Since rabbits are territorial animals, they may mark their territories along the borders of their pens or cages. They'll calm down after they get to know each other.
Step 3: Place both bunnies in neutral territory – an area of your home that neither rabbit has ever been in, like the bathroom, garage, parked car, or a hallway. Cover the neutral zone with newspaper, and introduce the bunnies to each other. Usually, they will sniff the area; then, one rabbit will express dominance by mounting or nipping the other.
Step 4: Let the rabbits bond for at least 20 minutes. If the rabbits start to bite each other or if you're afraid that their fighting is getting dangerous, spray their faces with water. They may stop fighting to clean up their faces, and the distraction may keep them from fighting again. When back in their cages, give them a treat.
TIP: Having a friend on hand who can help you separate the rabbits if they start fighting is also useful.
Step 5: After about a week, move the bunnies' cages or pens close enough so that they can sniff each other's noses, but don't let them be alone together unless you are home. Feed them at the same time so they'll get used to eating side by side. If you give one a treat, give one to the other, too.
Step 6: Return the rabbits to a neutral space every day for at least a week, letting them spend at least 20 minutes together and watching them carefully each time. Switch up the neutral location every couple of days. Remember that bonding may take a while.
TIP: When you see one rabbit grooming the other rabbit, it's a sign that the two have grown on each other.
Step 7: When the two rabbits are finally friends, start by putting them together in the same cage or pen only when you're home. Once they've shown they won't fight, they can share the cage or pen permanently. Keep two food bowls and two water bowls in their shared space so they don't quarrel.
Step 8: Many rabbit owners have observed that sick rabbits recover faster if they're allowed to stay with a bonded companion – even at the animal hospital.