““Unknown to either of them - but possibly not the dog - wife was pregnant.”
Dogs can smell *every* minute change in body odor.
She probably smelled like a veritable cloud of estrogen and progesterone to the dog.
Of course it knew.
My next door neighbors came over one night-she was pregnant with her first pregnancy, probably 3.5-4.5 months along. My dachshund , an unneutered male, loved those two almost as much as his human parents-he was always glad to see them. Well, he came over to them sitting on the sofa , sniffed her belly-looked up at her, puzzled, sniffed again...I watched him do this multiple times, and I noticed that his expression (dachshunds have some of the most expressive faces in dogdom) was becoming very accusing, almost angry.
I think in the dim depths of his doggy brainette, he thought she had eaten a 'human puppy'!