If the danish dogs and chiuaua dogs don`t can mix for impossible link, had been distinct species if were...?

Question

the only kinds of dogs in the world?

Answer 1

If I understand your question correctly, you are trying to determine what is the definition of a species.

Contrary to popular belief, inability to produce viable offspring is not the usual definition for distinct species.

Distinct species are reproductively isolated. That may mean that they indeed not be able to produce viable offspring. Or it may mean that they are geographically isolated. Generally, if two species do not mate and produce viable offspring in the wild, then they are reproductively isolated.

That is why wolves and dogs, while they can produce viable hybrids, are considered separate species.

Answer 2

I agree with the above poster.