By Francis Markus BBC correspondent in Shanghai

A new trend is sweeping China's largest city, Shanghai - keeping miniature pigs as pets.

The animals are known as perfume pigs because they allegedly do not smell.

They're not noisy like dogs, they're not fussy, they eat anything

Pet shop owner Wang Jianchu

The craze first started in southern China's Guangdong province, from where enterprising pet shop owners are bringing the animals, as fast as they can get them.

The trend is being spurred by the city authorities' strict regulations on keeping dogs, which owners are not allowed to take for walks in the streets.

The smell test

In a large Shanghai pet shop, a couple of dozen puppy dogs of all shapes and sizes compete for attention, but in their midst is a silent member of an alien species.

Pigs usually get cooked, not petted

I approach this perfume pig with a ribbon around his neck to undertake the smell test. He passes.

The pet shop owner, Wang Jianchu, says this little piggy is the last of a batch which he brought up from the southern boom city of Shenzhen, just across from Hong Kong.

He says he has had no problem finding homes for them.

"They're not noisy like dogs, they're not fussy, they eat anything, they don't bite people.

"And you don't have to get an expensive license as there is no government office in charge of perfume pigs."

Dog difficulties

For dog owners the city government's strict regulations barring dogs from being walked in the streets are becoming an ever bigger headache.

When he sweats, he does give off a fragrance; when you call him, he comes running

Pig owner

Dan Dan Chang, who owns a boisterous golden retriever called Danny, says some people take the risk of walking their dogs.

"But I wouldn't because you might have your dog taken away".

He says he would not consider substituting Danny for a perfume pig, "but they're exotic and cute and quite convenient to keep as a pet".

Pet shop owner Mrs Wu is very pleased with hers.

Entertainment

"He's funny, and when he sweats, he does give off a fragrance; when you call him, he comes running.

"If we're eating and we don't give him something too, he comes and butts us with his snout and says 'hey what about me?' He's a great laugh."

But the crucial sample group to be won over by any self respecting pet marketing guru is the primary school age group.

"I like them," says one girl. "I think they're quite like dogs, they're obedient."

Another girl is less sure. "I still prefer dogs, because I think they're more loveable than little pigs."

So, as with many things in Shanghai, it is a contest between those eager to try new things and those who prefer to stick to what they know and love.

But that is unlikely to deter the pet shop owners from bringing in fresh batches of perfume pigs, just as fast as they can get them.