E MICHAEL WITE RESPONDS:
Canine is a kind. There are over 500 variations of canine in the world and scientists believe that they all descended from a common ancestor,an original pair.
So not all 500 variations had to be aboard, only the pair.
And this holds true for every other kind.
Some have estimated, that leaving out all the species that live in the oceans and thus didn't need to be on the Ark, That leaves about 16,000 animals that were needed to be aboard.