I was looking up the differences in them a few minutes ago and there really isn't any, so much so that I'm not concerned with losing the Northern White Rhino su

I was looking up the differences in them a few minutes ago and there really isn't any, so much so that I'm not concerned with losing the Northern White Rhino sub-species. It's not a good thing, but we do have the required pieces to bring them back and if we don't then there is an identical animal which still has a decent sized population. I think the tolerance between species is highly variable, but "Fetuses of the Giant Panda have been grown in the womb of a cat by intercurrently inserting panda and cat embryos into the cat womb." http://en.wikipedia.org/wiki/Interspecific_pregnancy http://en.wikipedia.org/wiki/Interspecific_pregnancy However, wikipedia says: "Following the phylogenetic species concept, recent research has suggested the northern white rhinoceros may be an altogether different species, rather than a subspecies of white rhinoceros, in which case the correct scientific name for the former is Ceratotherium cottoni. Distinct morphological and genetic differences suggest the two proposed species have been separated for at least a million years." http://en.wikipedia.org/wiki/White_rhinoceros#Northern_white_rhinoceros http://en.wikipedia.org/wiki/White_rhinoceros#Northern_white...