Animal Instincts

Primates practice different mating styles but empowered females help create harmonious families. Humans could learn from them

- NATHAN H. LENTS

Heated disagreements about sexuality and gender are front and center in today's culture wars. Evolutionary biologist Nathan H. Lents argues in his new book, THE SEXUAL EVOLUTION: HOW 500 MILLION YEARS OF SEX, GENDER, AND MATING SHAPE MODERN RELATIONSHIPS (Mariner Books) that we need only look to the animal world to see that there's no one correct way to approach our sexual relationships. In fact, sexual diversity helps animal species thrive. In this excerpt from his book, Lents discusses two different mating styles that each contribute to strong parental bonds and shed light on the origins of the human family.

IN JUST TWO GENERATIONS, THE SEXUAL landscape has completely changed throughout most of the developed world, and so it is no surprise that many people find all of this terribly unsettling. What is surprising to me, however, is how little the biology and natural history of sex has factored into the public conversation. I assert that this moment of sexual turmoil is actually a rediscovery of the much more expansive relationship with sex that our ancestors once had and that other animals enjoy today.

In the modern world, much of how we express our sexuality, and how we form our sexual relationships, stems from cultural constructions, not innate biological wiring. Even a cursory glimpse of the sex lives of other animals demolishes any notion that sexual activity is narrowly purposed toward procreation. Biologists have discovered an ever-expanding list of reasons that animals have sex with each other. Animals use sex for bonding, social cohesion and alliance building. They use sex deceptively, competitively and financially. They even have sex for the same reason that we most often do it: just for the fun of it.