Not surprising the house rabbit society recommends it since it will be the pig most likely to get killed.

They are not similar at all, having different behaviour and dietary requirements. And the thought of a pig being used as a companion for a territorial rabbit makes my blood run cold - that poor pig.

Rabbits can kill pigs with a kick, either outright or by causing fatal internal damage. I have unfortunately been at the vets when the result of such an incident came in - the pig was gurgling and suffocating because it had been kicked breaking some ribs and puncturing a lung. Needless to say that will haunt me forever and the pig was put down. The kick probably won't be on purpose but as the rabbit Binky's about or moves normally. I know of 3 pigs who have been killed this way - none outright but through internal damage.

The diet is also a problem - guinea pigs cannot eat rabbit food as they must receive extra vit C from the mix and some rabbit foods contain anti-biotics fatal to pigs, also they need a lot of fresh veg daily, the amounts which would give a rabbit diarrhoea.

I completely disagree with risking guinea pigs lives by keeping them with/letting them play with rabbits (one kick is all it takes). A rabbit cannot communicate with a pig like it can another rabbit (and vice versa). And guinea pigs are highly social needing the company of their own kind.

It appears the two animals in the pictures are very happy together, but all it takes is for the much larger rabbit to accidentally strike the pig whilst hopping about and the pig will be seriously hurt/killed.

Pigs can live to 8 years or more, I wonder how long the average lifespan is when housed with a rabbit?