Sex is an animal instinct; rape is taking it when you want it against the persons will.
Kiwi, sex may be an animal instinct, but rape isn’t. Rape is rare in the animal kingdom. The male does not want to waste his sperm by raping a female who is not in heat, he will be wasting his sperm that way and miss out the opportunity to reproduce.
The male always seeks a female in heat. He wants to mate with a female in heat, that way he has maximum possibility that his seed will be carried forth.
Indeed, it is remarkable what a male will do to bring the female in heat, rather than raping her (which he could easily do, males in most species are bigger than females).
Thus when male lions take over a pride (having killed or driven away the males), the first thing they want to do is to have sex with the females of the pride. But they don’t do that, females are not in heat.
So they kill all the unweaned cubs. That puts females in heat, females want to mate, then they have sex with the females.
I remember seeing the courting ritual of rhinos. The female leads the male on a long chase; it may last for several kilometers, may last hours. It is a slow chase, the male does not try to catch up to the female, he pretty much follows her at her own pace. Female wants to make sure that the male has the endurance, the stamina; she wants the best genes for her offspring.
After a long and arduous ritual, the female is satisfied, comes fully in heat and the male mates with her. Any time during the courting ritual he could have raped her, but he doesn’t. If the female is not fully in heat, she probably won’t conceive and the male has wasted his seed.
Rape in animal kingdom, while it may occur is rare. As I said, rape is not a crime of sex, but a crime of power. It is very common among humans, but rare among animals.