What a horrible tragedy. Does this happen often in nature?
Only Nature know that answer.
Don’t know but my guess would be probably not, as the two would not be forced into close proximity of each other by Humans wanting them to get along and mate.....
Female would likely avoid the male completely if possible, and when she was ready to mate would the male smell and pursue her...
But that’s just conjecture on my part.
Not that often, no.
The big problem in captive situations (full disclosure, I’m a former keeper, and have one or two pet peeves), is that the so-called “Species Survival Plans” (SSPs) mandate moving around adult animals to new facilities to periodically ‘stir up the bloodlines’. Problem with that is that you’re breaking up bonded pairs, and expecting new ones to easily form from animals, who are strangers to each other. Unfortunately, that doesn’t always work, with the results you see here.
In nature the animals are exposed to mating at an early age. The male would have gotten his ass kicked by dominate males for years. He would have “ learned” to behave by now.