It turns out that one of the best ways to tell species apart is to examine their genitals. There’s an incredible variety of forms of male and female sex organs, even within the species gathered together in a genus, and so for years biologists have been separating, for example, beetles that otherwise look rather similar, into different species because their genitalia look and correspondingly work together completely differently. This holds true for humans and our closest relatives, the apes and other primates, as well.
It’s only been more recently that scientists have been looking at the reasons for all this genital variety. Menno Schilthuizen’s new book, published by Penguin, is a fascinating look at the evolutionary underpinnings of the “naughty bits,” which of course are only naughty in an absurdly Puritan culture like ours.
So they might not actually be naughty, but they sure are varied! I was continually surprised by the examples here — the aforementioned beetles and primates, plus squid, spiders, ducks (NSFW!), dragonflies, sharks, mice, snails, and more — all making us H. sapiens seem rather, as we say, vanilla. But only seems: research discussed here on human strategies — of sperm dumping, sperm scooping, etc. — what our bodies are up to without us having any idea of what’s going on, should make us question most of what we know, or rather assume, about human reproduction and sex.
Schilthuizen begins with fundamentals and definitions. Among these is that excellent question of why lifeforms even bother with sexual reproduction at all when cloning is just so much easier, particularly when we consider that the first instances of sexual reproduction were probably something like the way fish do it still, the broadcasting of eggs and sperm into the water, a rather random and wasteful approach. Yet the random mixing of DNA (culturally, we usually call this “making babies”) turns out to a brilliant way to counter the also-random dangers of the environment and breakdown-prone life-systems (disease, mutation). So, it’s actually a good thing, biologically, that your kid looks like the postman; it’s a blow against the enemy in the endless war against viruses, bacterium, mutations. Which reminds me of the bower birds: super-successful bower-builders do get the lion’s share of mating opportunities, but unsuccessful ones are still in the game, sneaking around while the master-builders are hard at work on their bowers. It’s a wide, wonderful world out there, and this book makes for great reading about it. I highly recommend it.
*On a personal note, I ran into Menno birding in Prospect Park last month. An ecologist and evolutionary biologist based at Naturalis Biodiversity Center in Leiden, the Netherlands, he was here in the erstwhile New Netherlands to promote his book and enjoy some of our fabled spring migration. I’m glad I asked this unusually well-dressed birder if he was seeing anything interesting — he said he was, because it was all interesting to a European used to a completely different avian fauna — since I hadn’t otherwise heard about this book. Check it out. And prepare to start thinking differently.