The golden lion tamarin is a monogamous primate. A male and a female will bond for life, mating only with each other, and cooperating to rear their family. Over 200 other mammal species are also monogamous, which is puzzling. Why do males stick around? In the news section of today’s New York Times, I have an article on two new studies on this mystery. It’s an example of science as a work in progress: the studies end up with very different conclusions. Check it out.