It is possible for rabbits to form bonds with other pets, particularly if they do not have companionship in the form of another rabbit...
It is possible for rabbits to form bonds with other pets, particularly if they do not have companionship in the form of another rabbit. The deciding factor in any relationship is the character and confidence of each animal.
Rabbits and guineapigs
It is often mistakenly believed that a rabbit and a guineapig will provide companionship for each other and be good "hutch buddies". Sadly, the guineapig is usually bullied by the rabbit, especially if the rabbit is unspayed / unneutered and takes out its frustration on the guineapig. The rabbit and guineapig may nip each other and cause wounds; they are not likely to cuddle up together and at best will tolerate each other.
Rabbits and dogs and cats
This is dependent on the placid nature and obedience of the dog or cat. It is important to introduce the rabbit correctly to the dog or cat so that they understand it is a member of the family and not to be confused with wild rabbits. Carry out introductions slowly and ensure that the rabbit is not getting stressed. You must trust your dog or cat completely if you allow your rabbit to run free with them and at all times the rabbit should have somewhere safe to retreat to; dogs and cats have been known to turn on rabbits even after years of trouble free companionship.
Often a surprising role reversal is seen where the rabbit becomes the dominant animal and bosses the cat or dog around. Rabbits have an element of self preservation and dominance in their nature which means they will often take the lead when meeting a predator animal and assert their authority immediately.