Mother Nature Is Trying to Kill You (5 page)

It especially bothers me to think of Sam and me as meat robots when I’m spending time with him. He’s a smiling, innocent, intelligent person, growing and learning and living right in front of me, but I keep overthinking things and looking at both of us as robots. Playing with Sam, reading him stories, chasing him, making him laugh—sometimes I’m with him, but I’m just not totally present because I know too well what’s really going on. Sam’s carrying 50 percent of my DNA, and my DNA is ensuring its own survival by making me think I love him. It’s hard to play along enthusiastically when you realize you’re a manipulated puppet.

And if that weren’t sad enough, I know that when Sam kisses me and smiles at me, it’s because his DNA is ensuring its own survival. We’re just a pair of meat robots. Like all the other animals, Sam and I are just selfishly going about our lives, using one another as prescribed by the DNA within us. The love we feel for one another, and everything about our beautiful relationship, all boils down to selfish greed.

I
. The profs have their facts straight. More than a thousand people were attacked by lions in Tanzania alone between 1990 and 2007 (Kushnir et al. 2010). Lions often hunt men guarding their cattle or children playing outside, but sometimes lions even pull people out of their beds. This inconvenient aspect of lion behavior throws a major wrench in conservation efforts, since the people who live in lion habitat have a very real incentive to get rid of them (Packer et al. 2005). Also, the top running speed of the African lion is 37 miles per hour (Garland 1983). Usain Bolt won gold at the London Olympics by running the 100-meter dash in 9.58 seconds. That gives him an average speed of 23.4 mph over the whole sprint.

II
. Male emperor penguins go without food for 105 to 115 days and drop from an average of 82 lb. to an average of 53 lb. Penguins are only able to incubate eggs successfully when they huddle with other penguins (Ancel et al. 1997).

III
. That study showed that the ability of the group to stay warm depended on multiple factors, including the speed of the wind, the number of penguins huddling, and the shape of the huddle as seen from above. Overall, though, an individual penguin’s movements could be best described by the rules I’ve mentioned. It’s impossible to know what a penguin is thinking out there, but they act as though they are trying to keep themselves warm, with no regard for other penguins (Waters et al. 2012).

IV
. This behavior is a big problem for zoos with captive zebras (Pluháčcek and Bardoš 2000).

V
. A lion cub normally has a 56 percent chance of living to the age of nine months. However, if a new male takes over the pride, the cub’s likelihood of survival plummets to 14 percent (Packer 2000).

VI
. It might occur to you that Scrooge technically remained selfish, even after the ghosts visited him. Once the ghosts pointed out to him that his money wouldn’t help him after he died, Scrooge decided to put his efforts into securing a comfortable afterlife. He never stopped looking after his own interests, he just shifted his focus from getting richer to getting into heaven. The fact that he suddenly became kind to everyone else was just a by-product of his selfishness.

VII
. Some thoroughly depressing footage of mice eating a baby albatross alive is available as “supplementary data” in a paper by Wanless et al. (2007).

VIII
. Even normal mice have been known to cannibalize one another. Mouse mothers frequently eat their own babies (Rowe et al. 1964), and adult-adult cannibalism happens too (Resendes et al. 2009).

IX
. When animals evolve themselves into a corner like that, it’s called selection-driven self-extinction (Parvinen and Dieckmann 2013).

X
. Interestingly, the North American extinction seems to have been caused by human activity in concert with climate changes that were happening at the same time (Faith 2011; Prescott et al. 2012). Those changes in climate were not caused by humans, though, unlike those happening in the world today.

XI
. To be clear, there are many women who would outcompete the average man in a competition of that kind (my wife, Shelby, can run faster and farther than I can, for example), but on average, men have the upper hand. In a random sample of men and women, you’d expect the fastest 10 percent to be made up of more men than women.

XII
. 
The Selfish Gene
(Dawkins 1976) is among the very best introductions to natural selection out there. The “meat robot” theme I use throughout this book is largely inspired by Dawkins’s shift in perspective from the individual to the DNA molecule. His book is definitely worth a read for that reason alone. As a bonus, it is the book where the term
meme
was first coined, so it’s interesting to read for that reason too.

Maybe you’re worried I exaggerated
the influence that DNA has on animals. Maybe you think that whole meat robot idea went a step too far. After all, animals have brains, right? Shouldn’t that put them in a position of control over a twisty microscopic molecule? I know, I’ve made a bold claim, so I’ll let the animal stories speak for themselves. You’ll see that DNA really is in the driver’s seat, and the best evidence of that comes from stories about sex.

Here’s what makes sex so interesting: animals, including humans, face a trade-off between how long they can live and whether or not they reproduce. If an organism were really in control, it would make decisions that optimized its own survival, and then only have sex if that didn’t shorten its lifespan. But that’s exactly the opposite of what we see in nature. Time and time again,
animals do things to pass on their DNA that cause their bodies harm. Animals will even die to have sex. Those animal decisions collectively build a convincing body of evidence that reproduction is even more important than survival; DNA really is in control, and the body really is just a meat robot. A sophisticated meat robot, but a meat robot nonetheless.

When I was a kid, I found it amazing that animals knew how to mate in the first place. It was no surprise to me that animals instinctively avoided danger, but for some reason I always had a hard time getting my head around the fact that animals instinctively know how to screw. Without training, animals know to thrust certain parts of their bodies against one another in very specific ways, so that sperm will come in contact with an egg. And it’s not just the screwing that comes instinctively either: that horniness drives a male satin bowerbird of Australia to collect anything blue it can find to decorate the ground outside its home—berries, flowers, Bic pen caps, whatever—because blue things will attract a female.
^I
Horniness makes male bighorn sheep smash their heads into one another’s because that’s how they can get a female.
^II
All of that happens instinctively. To me, it’s no surprise that animals are programmed to run away from predators, but I marvel at what they’re programmed to do for sex.

When I was about ten, I had the same thought about humans. How do they know what to do in bed? I remember thinking that people must have to pass on the secret of how babies are made from generation to generation so that we don’t go extinct. Otherwise, how on earth would anyone ever think to place a penis inside a vagina? Seriously? Who would ever think of that? I imagined scenarios where uneducated teenagers shipwrecked on islands would have no idea what to do. “Even if they did figure out to lie on top of each other,” I thought, “what if they didn’t know to take off their clothes? How would they figure that out?”

Once I hit puberty I realized my worry had been grossly misplaced. What I’d previously thought of as a very strange ritual between grown-ups had quickly become the only thing I could think about. In junior high my urge to have sex honestly felt about as strong as my urge to stay alive. My DNA had sent new instructions to my meat robot self in the form of raging hormones, and suddenly my whole soul was hell-bent on executing those directions. Girls were suddenly the only thing I cared about. I imagine that’s probably how powerful those urges are for satin bowerbirds and bighorn sheep.

This chapter is about lust—that DNA-driven, overwhelming urge to make babies that impels animals to hurt one another, hurt themselves, and even sacrifice their own lives. I’ll start by highlighting some of the most heinous sacrifices animals make for reproduction, from being eaten alive to having their clitorises torn open (you can decide which is worse). Along the way, I’ll challenge you to think about your own assumptions about sex and nature. Is there such thing as a natural childbirth? Are homosexual relationships natural? Is rape natural? You’ll quickly see that nature is
so immoral, vulgar, and downright wicked, we can’t possibly use nature’s behaviors to set rules for ourselves.

Here we go.

No animal makes a more stunning sacrifice for sex than the male antechinus.
¹
(If you want to say its name properly, make it rhyme with “acts of kindness.”) Antechinuses are cute. They live in Australia and pretty much just look like big-eyed, furry mice, but they’re really marsupials—pouched mammals more closely related to kangaroos and koalas than to mice. What makes antechinuses so unusual, though, is that every single year, they go through a mating season so intense that it kills every single male of the species.

Mating season is in August and lasts anywhere from three days to a couple of weeks. For a male antechinus that brief period is the only chance he’ll ever get to pass on his genes, so he sacrifices everything to give it his best shot. Testosterone levels skyrocket to ten times normal; sperm production goes into overdrive. As mating season begins, males are so full of sperm that a little bit leaks out of them every time they pee. The males need all that sperm, though, because antechinus mating is like a marathon; copulation lasts for six to twelve hours.

Hours.
(
I know
, right?)

That little mouse-sized ball of fur makes love like a tantric stallion. By taking his time, though, he defends that female from the advances of other males: mating season is so short that by staying attached to her for that long, he keeps other males off her for a significant fraction of the whole season. Also, that gives him
time to put a significant volume of sperm deep into her reproductive tract. Whether his genes or someone else’s will be passed on all comes down to his performance that week. He’s not out to impress anyone (though I, for one, am very impressed). He’s just doing it because he’s got to pass on his DNA.

Whether or not that male knows
why
mating is so important is up for debate, but what is certain is that it’s stressful for him. During mating season, male antechinuses experience off-the-chart levels of stress hormones. Those are the kinds of hormones released by people in the most stressful situations imaginable, for instance when people are displaced from their homes by civil war.
^III
Those hormones, which come from the adrenal glands, tell the whole body how to allocate energy when times are tough: “Stop spending so much on the brain, kidneys, and immune system. Let’s break down our fat reserves. Let’s get our muscles ready for action!” Those hormones can help an animal survive hardships in the short term, but they can also start to hurt the body if the doses are too high for too long.

To mate with a female, a male antechinus must first win fights with other males, and those high stress levels help him get the extra boost of energy he needs to do that. But somewhere in the evolution of antechinuses, the levels of those hormones that males needed to win those fights got out of control. Males suffer kidney failure, ulcers, immune system breakdown, and a whole whack of other problems all because their stress hormone levels are just too high for their bodies to tolerate. By the end of mating season, every male is dead, having lived less than a year.

In experiments, researchers have tried cutting off the testes of male antechinuses, and those castrated males survive the mating season without any problems at all. That’s the trade-off in a nutshell: if you want to mate, you’re going to have to do things that shorten your life. If the male antechinus meat robots were in control, they would skip the stress of sex to live as long as possible, but it’s their DNA behind the wheel, so the meat robots don’t get to make that call.