TRIGGER WARNING : Rape is natural

I recently had a conversation with someone who watched a few videos on how ducks, dolphins & numerous other wild animals force females into intercourse to reproduce, and have been just fine for hundreds of thousands of years.

This brought up an anger fued debate on how rape is natural within the human race. Yet my friend was adament that it was society abolishing nature's way of doing it.

I plan to show my friend this poll afterwards. Yet he will still argue that no matter how many people disagree with him, it's still natural and we are just thinking as a cotton ball society. What are some good argument points?

PS: My friend disagrees with rape and finds it disgusting yet still believes its a natural trait..