https://www.theguardian.com/notesandqueries/query/0,5753,-22904,00.html
According to Steve Jones in his book “Almost Like a Whale” the international committee which rules on taxonomic problems like this has decided that dogs are really just domesticated wolves that have been artificially bred into funny shapes, and consequently the species designation Canis domesticus (dog) has been formally abolished: they’re just a subspecies of Canis lupus (Wolf). The interesting bit of all this is that there is such a committee.
Christopher Young, Sheffield England
The dividing line between species is not always clear-cut, but is usually drawn at the ability to interbreed. Precisely for this reason, the domestic dog and the wolf used to be considered as seperate species, “canis familiaris” and “canis lupus”, but the dog is now regarded as a sub-species of the wolf species “canis lupus familiaris”.
Campbell McGregor, Glasgow Scotland
If their offspring aren’t sterile, they just might be members of the same species.