They are immensely cuddly. Not really. They're bears and they can be aggressive.
WWF, whose symbol has been the Giant Panda since it was founded in 1961, says:
As China's economy continues rapidly developing, this bamboo-eating member of the bear family faces a number of threats. Its forest habitat, in the mountainous areas of southwest China, is increasingly fragmented by roads and railroads. Habitat loss continues to occur outside of protected areas, while poaching remains an ever-present threat.
The biggest threat to pandas is the loss of the places they like to live.
And as one Chinese zoologist says:
There are no successful examples anywhere in the world of any kind of bear bred in captivity being successfully returned to the wild.
This is not a popular thing to say asstruggles to persuade Sweetie and Sunshine to breed, but I doubt whether their efforts will make much difference to a species whose numbers in the wild are down to about 16,000.
I don't doubt their dedication and I don't doubt that the pandas in Edinburgh are a huge attraction.
Why else would the zoo pay $1 million a year to 'rent' them from the Chinese?
And that's the secret really.
The pandas are PR for the conservation movement and they're brilliant at it.
Breeding programmes in zoos may not save the population in the wild from extinction, but by bringing millions of people around the world face to face with this charismatic animal they're sounding a very important alarm.