Why Is Sex Fun?が好きなら

To humans, the sex lives of many animals seem weird. In fact, by comparison with other animals, we are the ones with the weird sex lives. How did that come to be? We are the only social species to insist on carrying out sex privately. Stranger yet, we have sex at any time, even when the female can't be fertilized (for example, because she is already pregnant, post-menopausal, or between fertile cycles). A human femal…