Mother Nature Is Trying to Kill You (4 page)

Biologists visiting the island have watched this happen. A chick will sit defenselessly in its nest, while a mouse walks up and starts chewing on its torso. That attracts other mice, and soon a whole group of ten to fifteen mice will work away on the skin and connective tissue of a chick, battling one another for the meat, and eventually leaving a hole in the bird’s back up to two inches in diameter—that’s big enough that you can clearly see the internal organs through it. Not surprisingly, the bird soon dies from those injuries. This makes no difference to the mice, which just keep on eating until nothing remains but bones.
^VII

These aren’t small chicks either. Most weigh at least a pound, and researchers have even seen mice take out a juvenile albatross weighing more than twenty pounds! Because of that relatively large prey size, it can take the mice several days to kill a chick. To me that sounds like absolute torture, plain and simple, and seabird populations are plummeting on Gough Island as a result. But of course, the selfish mice don’t give a rat’s ass about that.

It sounds like paradise for the mice, finding themselves on an island with an unlimited food source, but it’s actually been pretty tough for them too. Not long after they arrived, the island became totally overrun with carnivorous mice, so it got harder and harder for individual mice to compete with one another. It was no longer enough to be able to digest meat. To survive, a mouse now had to be able to fight off mobs of other meat-eating mice. In general, larger mice had an advantage over the smaller ones in those fights, so larger mice got more food, made more babies, and the mice of Gough Island started getting bigger and bigger with each passing generation. Today, the average size of a mouse there is around thirty-five grams. That’s
two to three times
what a normal house mouse weighs. That increase in size happened over the course of just two hundred years. However, the greed that made them into superstars may well have also painted these mice into an evolutionary corner.

Because the mice are eating all the chicks, seabird populations are plummeting, and it’s pretty clear that the birds will be gone before too long.
¹⁰
That’s when things will suddenly get very, very bad for the giant meat-eating mice of Gough Island. At first they’ll probably just eat one another,
^VIII
but ultimately the island
will no longer be a place where carnivores can survive. Perhaps a few mice will revert to vegetarianism, but their large body sizes, and other body changes associated with carnivory, might make it hard for them to get enough calories on a vegetarian diet. If the mice had done a little planning, they could have lived merrily alongside the seabirds, eating plants and chick carcasses for centuries. But they didn’t, and couldn’t, plan ahead. There’s no long-term planning built into the process of natural selection. That’s where selfishness, even though it’s good for an individual in the moment, can be bad for a species as a whole.
^IX

Since the beginnings of life on Earth, the story of the Gough Island mice has played out countless times, but with other species in other places at other times. Animals move to a new environment and thrive, but their presence there changes things until those same animals can’t survive there anymore. And as humans, we know a thing or two about changing an environment once we get there.

When humans arrived in Australia, fifty thousand years ago, they began systematically wiping out all big animals.
¹¹
All nineteen mammal species there weighing more than two hundred pounds vanished soon after the arrival of humans. More than half of all species weighing between twenty and two hundred pounds disappeared as well. We know and love the kangaroos, koalas, and wombats of Australia today, but if humans hadn’t been such a plague on that continent, we’d also know a four-thousand-pound, hippo-sized wombat that stood six feet tall at the shoulder, a five-hundred-pound
kangaroo so heavy it couldn’t hop, and a lion with a pouch like a kangaroo’s. Some of those animals were hunted directly by humans, but humans also cleared trees and burned large areas for agriculture, and that would have wiped out many herbivorous animals by robbing them of the plants they depended on.
¹²
The Australia of today seems pristine and precious to us now, but its plants and animals are a small subset of what the first human settlers found there. I’ll say it again, because I think it’s hard to comprehend the first time you read it: more than half of Australia’s big, charismatic animals are gone.

North America suffered a similar fate when humans arrived there, between ten and twenty thousand years ago.
¹³
Mammoths, saber-toothed cats, and giant ground sloths all vanished within a few thousand years of human arrival, leaving the subset of animals we know there today. The pattern was similar to that in Australia, with everything over two thousand pounds disappearing, along with more than half of the species between seventy and two thousand pounds. Bison and grizzly bears and elk are pretty cool, but sometimes when you’re walking through Jasper National Park, in Canada, you can’t help but think it would be nice to have mammoths and camels around too.
^X

Animals have also vanished from the islands of the South Pacific as humans have colonized those islands over the last four thousand years or so. Most people have heard of the dodo bird, which went extinct on Mauritius, in the Indian Ocean, in the 1600s, but large, flightless birds were once quite common
on many islands of the South Pacific. Islands like Samoa, Fiji, Hawaii, New Zealand, and Rapa Nui (Easter Island) all suffered extinctions upon the arrival of humans.
¹⁴
In total, humans have wiped out roughly a thousand large bird species (including the dodo) from those islands, and extinctions of other animals, including bats, snakes, and many other animals, continue to this day.

Humans have a consistent track record upon arrival to new lands that makes us look an awful lot like the mice of Gough Island. But since humans really are just animals, it seems fair to say that human short-term thinking and greed are just our animal instincts shining through. In the pleasantries of modern society we may conceal our true colors, but fundamentally we’re all just giant mice. Proof of that lies in brief moments of panic, when humans act on their instincts. If you have any doubt of that, just look at the animalistic ways humans behave during shipwrecks.

When a ship sinks at sea, everyone knows the rule: Men are supposed to help “women and children first,” because otherwise women and children wouldn’t have a fair chance. It helps to be big and strong when you’re fleeing a sinking ship and getting to a life raft. You have to move quickly through corridors and up stairwells, perhaps with debris and other people in the way. There may also be swimming involved, in high ocean waves or frigid seawater. Since men are typically stronger and more aggressive compared to women (and certainly compared to children), this is where men would otherwise have an unfair advantage. So the “women and children first” rule is there to make sure men don’t act selfishly.
^XI

Here’s the natural experiment: If people are fundamentally generous, men should always help women in maritime disasters, so women should have higher rates of survival in those scenarios than men do. If people are selfish, men should survive in greater proportions than women. So what happens?

In a broad study of eighteen different maritime disasters spanning the 1850s to the 2010s, researchers found that the likelihood of survival for a woman was about half that of a man.
¹⁵
That suggests that even if men do save some of the women sometimes, they tend to save themselves in greater numbers. Similarly, crew members survive better than their passengers do, because they know where the life rafts are and how to work them. This isn’t just a problem from olden times either. In the 2011 sinking of the Russian ship MV
Bulgaria
, 60 percent of men survived but only 27 percent of women. In 2012, when the cruise ship
Costa Concordia
ran aground off the coast of Tuscany, its captain infamously got himself to shore well before the evacuation had been completed. Thirty-two people died.

Of course, everybody’s favorite maritime disaster is the RMS
Titanic
, which ran into an iceberg one chilly North Atlantic night in 1912 and then slowly sank, killing more than 1,500 people. It’s a tragedy, no doubt, but for some reason it’s a tragedy people can’t seem to get enough of. Well, if you’re looking for something about the
Titanic
to feel good about, try this: the RMS
Titanic
is one of only two disasters of the eighteen in that study where people actually followed the “women and children first” rule. The survival rate for women in that disaster was 70 percent, compared
to just 20 percent for men. So what made the
Titanic
special? Why did men follow the rules then, but not in other disasters?

The answer, it seems, may lie with an unlikely hero, the
Titanic
’s captain, Edward Smith. Shortly after the collision with the iceberg, Captain Smith gave an order to his crew that women and children should be saved first. His crew enforced that rule aggressively throughout the evacuation, effectively preventing selfish men from saving themselves. There are even written accounts of crew members shooting at men who tried to get on board the lifeboats that night. The crew enforced the “women and children first” rule so that selfish male passengers couldn’t act on their instincts.

It’s tempting to look at historical records like those and say, “Yeah, but
I’d
act differently,” but I challenge you to ask yourself if that’s really true. Drowning would be a horrible way to die. Whether you’re a man or a woman, would you honestly give up your seat on a life raft for someone you didn’t know? If you saw an empty seat on a lifeboat, would you really just walk away from it so a total stranger could live?

I suppose no one can really know how they’d act until they are in that position (heaven forbid), but I’d like to think that if I were in a shipwreck I’d do everything I could to save as many women and children as I could—men too, for that matter. But I think it’s fair to say that the second I felt like my own life was in danger, I’d get my ass on that lifeboat. Wouldn’t you? I want to be a good person and all, but fundamentally, I have a lot more invested in my own well-being than in that of some random person I don’t know.

Here’s where things shift, though; here’s where being a dad changes everything.

If I imagine my son with me on that hypothetical sinking
ship, not only would I let other people die so Sam could live, I would kill them myself, if I had to. In fact, I would even sacrifice my own life if it meant Sam would survive.

I think almost any parent would do the same for their child, and animals make similar decisions all the time. A songbird will try to save its eggs by dive-bombing an approaching cat, even though that puts the bird itself in danger. If a baby water buffalo is tackled by a lion, its mother will use her horns to gore that lion, despite the fact that the lion might turn to attack her instead. In life-or-death situations, parents instinctively put their own lives on the line for their young, because that’s often the greediest way to behave. After all, they’re not being greedy about surviving, they’re being greedy about passing on their DNA.

In fact, let me go one step further, and this is a bit of a mind bender, so bear with me: the animal isn’t the one protecting the DNA at all. The DNA protects itself. The animal’s body is an elaborate robot, made of meat and bones, built by the DNA to protect itself. That’s really the most accurate way to describe it. It’s a sort of meat robot.

The animals of the world, ourselves included, are kind of like those giant AT-AT walkers from
The Empire Strikes Back
. From a distance they looked like independent creatures, but they were really just four-legged vehicles, built and piloted by people, for a war against other people. You can think of our bodies the same way. Each of us is built by DNA molecules—DNA molecules that are at war with other DNA molecules. Animals’ bodies, our bodies, are just the meat robots of DNA molecules in battle.

There’s an important difference between AT-ATs and animals, though. During a battle, AT-ATs are piloted by the people inside them. DNA can’t do that because DNA really has no idea
what’s going on out there. Instead, the DNA builds its animal to function autonomously. It’s built with an innate set of urges and instincts, like the urge to breathe, the urge to avoid pain, and the urge to have sex. Those instincts keep the animal alive and coerce the animal to reproduce. As a result, the DNA survives and is passed on to the next generation, so it can make the next generation of AT-AT-like meat robots.

When you look over the rail of a high balcony and feel your very soul pulling you back away from the edge, that’s your DNA’s programming at work. When a new crush takes over your whole world—and when holding hands with that person makes you feel like your heart’s going to explode—that’s the DNA pushing your buttons. To call them “urges” almost doesn’t give them enough credit. They’re instincts. They’re the things that matter most to us—life, love, and sex—and they’re all just programs written into our meat robot bodies by the DNA inside us.

I was first introduced to this way of thinking about twenty years ago by the book
The Selfish Gene
by Richard Dawkins, and ever since I read that book, I’ve seen myself differently.
^XII
For example, if I’m feeling stressed about a big talk I need to give or about a meeting with my boss at work, I always seem to be able to step outside the situation to see myself as a worked-up meat robot. When I do, I somehow let go of a bit of that stress. When I see myself as a programmed machine, the stakes seem much, much lower.

That way of thinking has thrown me for a loop since Sam was born, though. I don’t like to think of my parenting skills as DNA-written urges. It’s depressing to think I love my son simply because that’s what my DNA tells me to do, because that means it wasn’t really my decision to love Sam at all. It means I’m a zombie, caring about Sam because my DNA wants the copy of itself within Sam to survive. That’s just sad.