"Question: is there any evidence whatever to suggest that any other animals are aware of any connection between sexual activity and pregnancy?"

No evidence that I am aware of. I tend to doubt that any animals really make the connection. Since such a relatively long period of time takes place between mating and birth, I doubt that it occurs to an animal that there is a cause-and-effect relationship between the two.

Anecdote:

The heavily pregnant Mrs. Yeokum makes her annual eight mile trek down the mountain to the settlement infirmary to deliver her nineteenth child. The nineteenth time she has made this journey since she was married at the age of fourteen.

It was an easy delivery as usual, she being a healthy, robust, and still relatively young woman. As the doctor wrapped her newborn baby in a blanket and gently handed him to her, he said, "Well, Mrs. Yeokum, I guess we'll be seeing you again next year, eh?"

She responded, "Nope!"

"Oh?" said the doctor, "Aren't you planning to have any more children?"

"Nope!" she said. "We found out what was doin' it!"

Don Firth

P. S. There might be a folk song in there somewhere.