Genetically the cross is theoretically possible. The difference in size of the individuals, especially the reproductive organs creates a barrier that prevents crossing.
If the differences had been created via natural selection not artificial selection, a great Dane and Chihuahua would likely be listed as different species or subspecies for the same reasons.
Dogs would be a good example for ring species, which show the outer limits of the species definition, if they they occurred in the wild in their many diverse forms. But since they are not, I’d group them as one species still, as their origin is artificial and so are, at least partly, their means of reproduction.
In theory: yes, most likely. In practice? No.
Genetically the cross is theoretically possible. The difference in size of the individuals, especially the reproductive organs creates a barrier that prevents crossing.
If the differences had been created via natural selection not artificial selection, a great Dane and Chihuahua would likely be listed as different species or subspecies for the same reasons.
Dogs would be a good example for ring species, which show the outer limits of the species definition, if they they occurred in the wild in their many diverse forms. But since they are not, I’d group them as one species still, as their origin is artificial and so are, at least partly, their means of reproduction.