Krishna
This is a very different book by Jared Diamond, whose earlier work Collapse we have reviewed here before. It is also a very slim volume so takes less time to read.
Some more 'meta thoughts' on the book first, and then we will get to the gist of the arguments.
I also think that the title is not what the book is about and it is surprising that Jared would resort to the equivalent of click-bait to attract more people to read this book, if this is the case. It is a very scientific investigation of reproductive features in mammals, including humans. Of course, you don't expect an erotic book from Jared (or do not pick up this author if you did want one of those) but still, I think if you accidentally picked up a tome, I guess it would be like asking Nietzsche for a sex story.
It is a slim volume but still interesting. Jared shows that, compared to the animal kingdom, humans have really weird sexual practices. Monogamy is one. Also the practice of considering sex as private is another. Humans also engage in sex just for the fun of it, unlike other animals which do it only for procreation and many animals separate and go their own ways after the act. And humans engage in it even after menopause (a state that does not exist in most animals).
They do it all around the year and not just during the period when the female is fertile.
Jared points out that even cannibalism during or after sex, as happens in some spiders and with praying mantis, is explainable in terms of gene propagation success. He claims that in many cases, the male makes it easy for the female to eat him and explains why it is a good evolutionary strategy if not a good personal strategy for the male.
When it comes to humans, Jared explains how the Y chromosome starts to identify the fetus as a male and then produces enzymes to take them on that path. That way female seems to be the default gender and the Y chromosome directs constructions to a masculine path with the building of testes, testosterone and all the things that go with males biologically. He also talks about defects that exist in some humans which produces pseudo hermaphrodites. This is truly fascinating. One type of these people definitely look like women and outwardly have all woman parts including breasts and vagina but these are "men" who started on that path but were blocked by absence of an enzyme or other construction. The only time they realize - and others around them too - that they are not female is when they fail to menstruate. They lack an ovary or Fallopian tube and so they cannot go through menstruation or pregnancy. Truly devastating news, it must be, when the doctor reveals them the cause of their lack of menstruation.
Jared also talks about lactation in non pregnant and even unmarried or menopausal women and how it came about in the cases known to the world. Even the bible, according to the author, mentions it!
Jared discusses why humans, and some high primates close to us, have a concealed ovulation cycle and discusses two popular theories for this evolutionary trait - husband at home or many husbands. They are diametrically opposite and also logically explainable!
Quite a bit of these discussions are professorial and pedantic; not for the easy reading on a beach or a relaxed afternoon. Even for those interested in the scholarly discussion that Jared normally provides, I would assume that some pages here would be tedious.
He makes surprising claims - not in the main book, which is reasoned and scholarly, but in the analogies he reaches for. In the trade off between body repair and increasing offspring capacity that nature has to do for all creatures, he offers this surprising analogy : " If you are a taxi driver in Teheran, you don't waste your money maintaining your taxi where even the most careful taxi driver has to face a fender bender every few weeks. Instead you save money towards your inevitable next car". Hmmm….
The book ends with comparing 'Fisher's runaway selection model' in animals and men. This model postulates that to attract females (primarily) some decorative features go out of hand to either waste precious evolutionary resources in signals that are not directly productive to the survival of the animal or even hinder it in some way, increasing the danger'. Examples are of course the extravagant tail of the male peacocks that impede the bird's flying ability or even navigation through the bushes or the widowbird's sixteen inch tail. His speculative answer may surprise you.
A highly erudite discussion of human and animal sexuality in evolutionary terms. If this subject interests you, you will not be disappointed.
6/10
-- Krishna