Lents applied the “Page 99 Test” to his new book, Not So Different: Finding Human Nature in Animals, and reported the following:
On page 99 of Not So Different, I discuss how some species of fish have three male genders, that is, three versions of the male body type with different markings, different size, different behaviors, and different strategies for being successful at their ultimate goal: reproduction. This is a perfect window into one the themes of the book: when it comes to how animals live, there is much more than meets the eye. As stated on page 99, "Experienced anglers can easily tell the difference between males and females [in bluegill sunfish]. Or so they think. Many of the fish they identify as females are actually helper males. In sunfish, the alliance-forming ritual between large [males] and helper males is a courtship dance that includes genital contact. Quite often, when a female joins the picture to contribute the eggs, the sex is a three-way affair."Visit Nathan H. Lents's website.
At the same time, page 99 is not very representative because it speaks of fish, when most of the book is about birds and mammals, especially primates. Not So Different explores the emotional and social lives of other animal species to reveal how closely their behavioral programs mirror our own. Other animals understand fairness, feel love, grieve their dead, and communicate with rich vocabularies. The cognitive and emotional differences between humans and other animals are only in degree, not in kind.