Once and for all – are we monogamous or polygynous? David Barash answers the age old question in 200 pages of research and facts from all over the world, from all over the animal kingdom, and from all over the human psyche. The answer appears to be yes.

It’s a big world, and you can find support for pretty much any kind of sexuality and hierarchy you espouse. But one trait stands out; mammals tend to be polygynous. Polygyny is a branch of polygamy, where males take multiple mates. Much rarer – but still visible – is polyandry, in which females take multiple mates.

The book ranges far wider and deeper than expected. Chapters cover the violence of males, the range of parenting instincts, the way adultery is treated by species of all kinds, and how God fits the framework.

Throughout history, it appears that most men ended up with one wife. This was not so much because it was right or desirable, but because the alpha-male harem-keepers took far more than their share (sometimes tens of thousands!), and everyone else was lucky to hook up at all. Having a lifemate is clearly advantageous, and keeps men from going even farther overboard. Barash cites Engels saying maybe it’s not religion that’s the opiate of the masses, but monogamy.

Barash says we are confused over the most basic trait of any being – reproduction. Our advanced brains have taken us places we were perhaps never intended to go. This has muddied the basic functionalities of our animal roots. No other beings are as uncertain about reproduction, have so many myths, customs, rituals and taboos around it, or have such a constantly evolving relationship to it. Cultural evolution has led Homo sapiens to monogamy, while its instincts remain polygynous.

The book is packed with ideas, facts, quotes and allusions. Every paragraph is a challenge to knowledge. It is one of those science books where there is no point using a highlighter; the entire book would be soaking in yellow and you couldn’t find a thing.

David Wineberg ( )