You might remember UC Riverside Biology Professor Marlene Zuk's book Sexual Selections. It told the story of gay penguin partners Roy and Silo.
Zuk is out with a new book called Sex on Six Legs. In this volume, Zuk writes about the relationship between animal sex and human sex. Below is an interview in which the author discsses animal sex. If you want to know more, you'll have to buy the book.