Neil DeGrasse Tyson, who himself is an expert at debunking flawed theories (sorry, B.o.B.), for once seems to have spoken too soon. Yesterday evening the renowned scientist and coital expert tweeted that if any two members of a species experienced pain during sex, that species probably died out.
Tyson immediately received angry replies from animal scientists pointing out that no, sex is not pleasurable for all animal species. Male cats, for example, have tiny spines on their penises, which is probably a little uncomfortable for the females. And then there are male ducks, which plant their sperm in female ducks by force. And male bedbugs, which literally pierce a female's abdomen to impregnate her, leaving an open wound.
So no, Neil, not all animal sex is pleasurable. Not even all human sex is pleasurable. Consider your tweet debunked.