One of the hottest fronts in the modern culture wars is S ex and gender. Frans de Waal, a Dutch-American primatologist, walks calmly through the bloody battlefield, avoiding banned books, anti-transgender laws and political doublespeak.

If it didn't spark debate, de Waal's new book would probably fail. It seems safe from death since it is dividing opinion before it is published.

I found the book to be as wise as it was humane, according to the American primatologist Sarah Blaffer Hrdy.

The primatologist is full of admiration for de Waal's descriptions of ape behavior, but feels the book falls short when it comes to humans. He told me that the author had a chance to present a thorough and thoughtful discussion of the latest research.

This book is an attempt to put the sex back into gender. For too long, de Waal thinks, gender was seen as a purely social construct and talk of inborn sex differences was taboo.

He argues that gender is a spectrum, and that sex is 888-609- 888-609- 888-609- 888-609- 888-609-. The fact that the latter grew out of the former should not stop us from questioning the cultural components of gender, some of which are based on a misunderstanding of biology. It doesn't mean better or worse.

He makes this case by reference to non-human primate he has observed for decades, but the book is also a plea to us to look beyond Chimpanzees when searching for parallels in our nearest primate relatives. We are just as close to bonobos as the Kama Sutra apes for whom sex is as boring as a handshake.

Chimpanzees became our go-to model of primate behavior because explorers stumbled on them first, according to de Waal. He feels that the skewed emphasis gave rise to an unjustifiably bleak view of human nature, which has only begun to lighten up in the last few decades. He compares himself to a frog he once saw in a bowl of water. Like the frog, he has been through a lot.

From the first page of Different, you know you are in the presence of someone who feels beyond the culture wars.

The typical primate society is at heart a female kinship network run by older matriarchs

He's well-known enough to feel comfortable sharing personal reflections on growing up as one of six brothers and describing himself as a feminist who still refuses to devalue his own gender. The idea that gender is socially constructed until it comes to gender identity and sexual orientation is something he dislikes.

It is acutely aware that who is looking is as important as what they see, which is why primatology was founded by men but came to be dominated by women. The 73-year-old white man iscis gender straight. He told me that when the women came, they got more interested in female-female and mother-offspring relationships.

His descriptions of apes are captivating. Princess Mimi, the bonobo with staff, grew up pampered in a human home and was puzzled by the retinue of males with obvious erections she acquired on meeting her own kind.

The complexity of sex and social behavior in other apes is brought to life through these characters. He recounts how a group of disgruntled underlings chased a young and possibly overpromoted alpha-male chimp up a tree.

bonobo juveniles hugging at the lola ya bonobo sanctuary, democratic republic of the congo.

Bonobo juveniles hugging, Lola ya Bonobo sanctuary, Democratic Republic of the Congo. Photograph: Anup Shah/Getty Images

After about a quarter of an hour, Mama climbed into the tree. She kissed him. He followed her down while she climbed down. Nobody resisted when Mama brought him with her. He made up with his adversaries. No other chimp in the group could have done that.

Orange was the alpha female of the large macaque troop, while Mr. Spickles was the alpha male. The males and females looked at each other. Orange was Mr Spickles' most important political ally.

Orange and Dandy were almost half the age of Mr Spickles. Orange would seek out her younger mate again if Mr Spickles tried to chase him away. Orange would take up position next to the aging alpha if Dandy were to flaunt his youth in front of Mr Spickles. She never confused the two.

Both males and females strive non-consciously to maximize their evolutionary fitness, but because they differ biologically their methods for achieving this goal differ too. The typical primate society is at heart a female kinship network run by older matriarchs, which is why one rule holds across species.

The hierarchy of males and females is based on more than just physical prowess. It counts, as well as prestige, which is less visible. As Mama and Orange showed, prestige always has a component of altruism and community-mindedness. The alpha female is below the alpha male. She has a choice. The order has been reversed byBonobos, who invest everything in the group.

We have no evidence that any species other than our own knows that sex leads to progeny

In her book Bitch, the British zoologist Lucy Cooke argued that the female has been underestimated. We have gone wrong at a deeper level. He argues that nature and nurture are entwined in both humans and non-humans. There are hints of cultural variation in the way the sexes behave in non-human primate, though he says it hasn't been studied enough yet.

De Waal says that we are more similar to other primate than we think. He once came up with a term for those who warned against the use of stereotypes. Humans seem to be unique in one way. We are the only ape that puts labels on sexual or gender diversity. He says that he doesn't find the kind of tolerance we have in human societies in other primates.

He expects a backlash from the feminists who he criticizes in the book and the conservatives who wrongly claim that science supports their position. Critics are closer to home.

Black fails to ask the most fundamental question: what is biological sex? She doesn't think it's right to assume that sex is a two-dimensional thing, even if de Waal does allow for some blurring.

There is a large body of research on human sex and gender, including work by the American neuroscientist Lise Eliot and British psychologist Cordelia Fine.

man with chimp's head

What animals can teach us about politics.

To understand that the non-human natural/human-cultural division is a straw person argument, is to read these and other researchers. In the introduction to Different, de Waal states that he will not discuss areas of human behavior for which there are no animal parallels.

The controversy surrounding the book will definitely dominate the discussion, so now is a good time to point out some of de Waal's quieter but still thought- provoking observations.

Different is a good read if you agree with him. The description of two grizzled male chimps who were normally sworn enemies, arms slung around each other's shoulders, forming a barrage between a newborn and a young alpha male with possibly infanticidal intent, is one of many that will be hard to forget.

  • Granta published Different by Frans de Waal on May 5. You can support the Guardian and Observer by ordering your copy at Delivery charges may apply.