Under Arctic Ice is another early Astounding Stories piece, by Harry Bates and Desmond P. Hall under the H. G. Winter pseudonym. The hero is more sympathetic than their Hawk Carse stories--an ordinary man with an extraordinary tale, scorned. He rises to the occasion. It lacks the prevailing cultural biases of the time, but that actually makes it less interesting. Pretty much skippable.
Favorite Stories: Kij Johnson, The evolution of trickster stories among the dogs of North Park after the Change
Now THIS is a good one. It haunts me to this day. Most stories about speaking dogs kind of assume we'd get comfortable with the idea. This one is more complex, the dogs have their own interior lives we just can't quite handle. And cats are just right out. If you really want to think hard about our relationship with animals, this would be the story to read.