What are you defining as “rape”, here?
Dolphins will indulge in sex play with each other, and I know from experience* that dolphins will do the same toward humans. (“sex play” here mainly being bumping or rubbing up against other swimmers with erect penes.) I was told that this sort of sex play toward humans is more common with hermit dolphins or dolphins raised in captivity.
But, AFAIK, there are not roving pods of dolphins looking to give surfers a good rogering, or seeking in vain for human blowholes, or whatever.
- one of those “swim with the dolphin” experiences, specifically. dolphins, BTW, are quite big. and suddenly sharing your waterspace with a big dolphin’s big wedding tackle is quite startling. and a good party story.
but “oh no, flipper!” never actually rubbed up against any of us. I think he just sort of wanted us to know it was there, and went back to swimming about and vocalizing after waving it around at us.