Just found this
article on human sexuality. Fascinating! Now I want to go read that book.
Short excerpt:
“No animal spends more of its allotted time on Earth fussing over sex than Homo sapiens,” they write. In fact, the animal world is filled with species who confine their sexual behavior to just a few periods each year, the only times when conception is possible. Among apes the only monogamous species are the gibbons whose infrequent, reproduction-only copulations make them much better adherents of the Vatican’s guidelines than we are.