[PatrickHenry]

However, they [Saint Bernard and a chihuahua] can still interbreed and indeed create fertile offspring, even if the 'act' itself has become somewhat cumbersome due to the enormous difference in size.

I've read that it's only possible if the female is the St. Bernard. She's large enough to produce live offspring. But a female chihuahua, assuming she somehow survives an encounter with a male St. Bernard, isn't be large enough to drop the resulting litter. Otherwise, I think that at the genetic level the mating is no problem at all.

[wai-ming]

I think that at the genetic level the mating is no problem at all.

Very interesting.

I wonder what the pups resulting from such a union would look like.

[Junior]

St. Barnard - Chihuahua: A ring species in the making.