Why keeping a rabbit and guinea pig together is not a good idea…

Rabbits and guinea pigs look rather similar and have very similar lifestyles – after all, they're both small furry pets that eat hay and vegetables. Un-neutered rabbits kept together will often either fight (if the same sex) or multiply uncontrollably (if opposite sexes), but get lonely and pine if left on their own. So surely they make the perfect companions?

Sadly, no. Although it looks like a match made in heaven, if things go wrong it can be closer to hell – for the guinea pig!

So what's the problem?
There are three good reasons to keep them separately – dietary needs, disease and behaviour.

Dietary Needs:

Although both rabbits and guinea pigs are herbivores (plant eaters), there are significant differences. The most important is that rabbits can make their own Vitamin C – guinea pigs cannot. Without the vitamin in their diet, guinea pigs will get their version of scurvy, becoming listless, getting diarrhoea, losing their hair and ultimately even bleeding to death internally. If you're keeping them together, you need to feed both on guinea pig food (fortified with Vitamin C), otherwise there is the risk that the rabbit eats the guinea pig's food, leaving the less appetising (and unfortified) food for the poor guinea pig. Feeding guinea pig food to rabbits isn't harmful (especially in the short term), but it isn't a well-balanced diet for them.

Disease:

Both species can carry the same diseases, and transmit them to each other. However, while conditions such as Pasteurella affect both equally, some conditions (like Bordetella bronchiseptica – a cause of kennel cough in dogs) are much, much milder in rabbits (so they appear healthy) but are potentially fatal in guinea pigs.

Behaviour:

This is the most important factor. Guinea pigs and rabbits may look superficially similar to us, but their behaviour and body language is very, very different. To make matters worse, rabbits are (in general) much bigger and stronger than guinea pigs, and can cause severe injury to them – even if thumping in play, the rabbit's strong hind legs can cripple or kill a guinea pig.  How would you like to live in the same house with a bad tempered gorilla? That's what it feels like to a guinea pig living with a rabbit!

Because the body language is different, they don't communicate effectively; this can lead to the rabbit becoming frustrated, and they may attack or bully the guinea pig. Rabbits like to groom each other and enjoy close company; guinea pigs generally prefer to keep themselves to themselves – even if the rabbit's being friendly, the guinea pig may feel harassed (like the gorilla insisting on looking for insects in your hair when you just want to watch TV…)!

This confusion can also lead to other mistakes – it is very common for male rabbits to try to mate with female and male guinea pigs, to the injury of the poor guinea pig (who was happily pottering about his normal life when suddenly jumped and mounted by a large, heavy, randy buck). This isn't just unpleasant for the guinea pig (remember the gorilla) but potentially dangerous – it is sadly quite possible for a guinea pig's back to be broken during the attempted mating.

Bottom line – rabbits and guinea pigs aren't really compatible!

Mine have always got on fine together!
If you've got a guinea pig and a rabbit who already live together happily without any issues, it's usually because they got to know each other when very young, have adapted to each other, and are fairly good-natured to begin with. It is vitally important, however, to make sure the guinea pigs have a refuge area to hide away in – a pipe, pen or box with an entrance large enough for them but too small for the rabbit. If you see that they are spending all their time in the refuge, it may be that life is not as harmonious as it looks on the surface…

But we've always kept them together…
Lots of small children play with matches without burning themselves, but that doesn't mean it's a good idea. It's the same with rabbits and guinea pigs!

So should they be kept on their own?
Definitely not! Both should have company – but of their own species. Neutering of rabbits is a routine procedure nowadays (and if you're not planning to breed is really important for health in does (females) who are prone to all sorts of nasty gynaecological conditions). Neutered rabbits cannot breed, and are much less likely to fight, but can communicate, groom each other and run and play together. Meanwhile, the guinea pigs can live together and get on with their life unmolested!