Mother Nature Is Trying to Kill You (13 page)

III
. Common vampire bats almost always feed on cattle, and that presents a wonderful mystery: since vampire bats only live in Central and South America, and since there were no cows in that part of the world before 1492, no one knows what vampire bats fed on before livestock was brought from Europe. Biologists assume that vampire bats originally fed on all kinds of different rainforest mammals, and that they switched over to cattle once the cattle were introduced. Imagine eking out an existence drinking blood from well-hidden, small rainforest mammals that can bite you back, and then suddenly having giant, defenseless cattle brought in. It would have been like getting a McDonald’s drive-through in your neighborhood. Today, it’s almost impossible to find common vampire bats that don’t get all their food from cattle, so we may never know what the original food of vampire bats was.

IV
. A non–Gough Island mouse, that is.

V
. The book was
Just Bats
by Brock Fenton (1983). After I read it, I contacted Brock and told him I was interested in learning more about bats. He was very supportive. Years later, he invited me to do my master’s degree with him. He was the one who sent me on this very trip to Costa Rica.

VI
. The fact that vampire bats can’t taste anything was uncovered by a guy with whom I did my master’s, John Ratcliffe. The experiment is pretty simple: you feed an animal something with a strong flavor, and then you make it feel sick. Afterward, it won’t want to eat anything that tastes like that. You know how your uncle Bert can’t stand the smell of tequila because of a bad experience he had in Mexico that one time? Same thing. To date, vampire bats are the only animals ever found that don’t learn to avoid a particular taste after repeated experiences of sickness (Ratcliffe et al. 2003).

VII
. I say “she” because only female mosquitoes bite humans. Mosquitoes of both sexes eat fruit juices and nectar, but females also feed on blood to get iron and a few extra proteins for laying eggs.

VIII
. I say “painlessly” because the show about parasites I work on,
Monsters Inside Me,
once featured an interview with a guy who got a leech up his nose in Nepal. He didn’t even know it was there until he started getting nosebleeds, and then later periodically saw it stretching out of his nose, waving in front of his face. Throughout his experience he felt no pain, so I assume the animals upon which these leeches typically feed also feel no pain.

IX
. In fact, the Greek word
schistos,
which gives schistosomes their name, translates as “split” or “divided.”

X
. It was in the tiny village of Kianjavato, and we were there searching for the elusive Madagascar sucker-footed bats.

XI
. If cat urine does turn you on, I’m afraid you’ll need to find a different excuse. Sorry.

One of the classic arguments
people use to try to prove that nature’s actually really nice to us is the wealth of foods she provides. You can load up your grocery cart with fruits, vegetables, breads, cheeses, eggs, meats, and all of them came from the natural world. Even the high-fructose corn syrup in your gummy bears came from a plant. It’s a fair question: If Mother Nature’s so selfish and violent, why does she do such a wonderful job of keeping us alive?

That supposed care she provides is an illusion. She’s not really trying to feed us at all. Instead, we’ve just become masters of working nature over to feed ourselves. Plants and animals weren’t put here to take care of us. They appeared as the result of evolution, just as we did. They are other kinds of meat robots doing their best to survive and reproduce, just like the rest of us. (I
suppose it’s a little strange to call a plant a “meat robot,” but I’m going to do so anyway, just to be consistent about the relationship between DNA and the body it makes.)

Plants are selfish, so they go to extraordinary lengths to
avoid
getting eaten. They produce everything from thorns to poisons to keep animals away. In response, we’ve learned to avoid most of the plants altogether and focus instead on the small minority of plants that we can eat. We actually don’t eat very many kinds of plants at all. We’ve selected a very small number of plants that don’t hurt us and then bred them to make them even more delicious.
¹
For instance, cabbage, kale, broccoli, cauliflower, brussels sprouts, and kohlrabi all come from the same species of plant,
Brassica oleracea
. The plants aren’t trying to help us; we’re helping ourselves.

As for the animals we eat, I think it’s a safe bet that they don’t really want to be eaten by you or have their unborn babies made into omelets or have the milk they make for their own babies mixed with your coffee. Fish may be a great source of omega-3 fatty acids, but those molecules aren’t inside that fish for your health. They’re there because they’re good for the fish. When you go for sushi, you’re stealing parts from that fish’s meat robot and incorporating them into your own.

Plants and animals make us healthy because our bodies have evolved in direct response to the plants and animals we eat. We’ve been killing and eating nature’s bounty for millennia, so human bodies are built to thrive on precisely those kinds of foods. To say nature is there to make us healthy has it backward. Our bodies are built to steal from the other bodies around us: we can only survive by eating plants, animals, and fungi.

But we’re not the only ones out there with an appetite. To
get a clear perspective on our own gluttony, it helps to first see how intense gluttony can get in nature. That’s what this chapter is about—gluttony in the natural world—starting with plants that make their own food, moving up through the plant-eating animals, the animal-eating animals, and finally to the animals that dine on the corpses that are left behind in the carnage. Gluttony abounds.

There’s a man in India named Prahlad Jani who has consumed neither food nor water since he was eleven years old, in 1940. How do we know this? Because he says so. Mr. Jani says he gets all his energy from the sun.

That seems like it should be impossible, but there’s a physician in India, a
neurologist
in fact, named Dr. Sudhir Shah, who has verified Mr. Jani’s claim on two separate occasions. Over the course of ten days in 2003 and fourteen days in 2010, Dr. Shah and his team watched Mr. Jani carefully and confirmed that he survived with no food or water.

Well . . . no water
except
the water he got each day to rinse out his mouth, but he promised not to swallow any of that. Also, he got to bathe himself, but other than those two minor details, he had absolutely no food or water at all over the course of those two studies.
²

Now, for reasons you might be able to guess, neither of Dr. Shah’s studies has quite made it into a scientific journal, but Dr. Shah has published a PDF on his website, explaining how Mr. Jani might have turned himself into a “kind of solar cooker” with “solar batteries.” 
³
This story has been covered by newspapers and
TV programs around the world, and some people actually believe it’s true.

Of course it’s not, though.

I don’t know if Mr. Jani is a fraud or if he is suffering from a mental illness that makes him unaware that he eats and drinks, but I do know that humans use energy to stay alive, and I also know there’s no way for a human to get energy from a beam of sunlight.

As for Dr. Shah, he’s either in on the lie or he’s not a very good doctor (or both, I suppose). A human cannot go decades without food or water. That seems like the kind of basic fact about humans that a doctor should know. I don’t think I’m being unfair about this.

Humans need water. A person with no access to water at all may die in less than a week. Our bodies are mostly made of water, not 99 percent as the urban myth goes, but closer to 60 percent (the proportion changes slightly with health and age).
⁴
And that water is constantly streaming out of us: as urine, feces, sweat, tears, the humidity of our exhaled breaths, and for women, during menstruation. With so much water leaving the body, our food and drinks need to bring in at least 2 to 3 liters of water per day (that number can vary, but 2.6 liters is the number scientists have used when trying to estimate how much water astronauts will need).
⁵
That’s about five and a half pounds. During heavy exercise or in hot climates, those water needs can more than double.
^I

In addition to water, humans also need food, because that’s where we get our energy. A person on a hunger strike (drinking only water) usually dies after a month or two, having burned up all their energy reserves. Even just sitting around, a person burns through the equivalent of around 580 AA batteries each day.
⁶
With daily activities factored in, like walking, talking, working, and all the other things a person does, daily energy costs can be two to three times higher than that. It’s simple physics. Energy cannot be created or destroyed. Since Mr. Jani’s body uses energy, he has to consume energy.

Mr. Jani’s claim is that he gets his energy from sunlight. Plants can do that, but animals like Mr. Jani cannot. The process by which plants do that is called photosynthesis.
^II
Photosynthesis first evolved about 2.4 billion years ago, so long ago that everything living on Earth still had only one cell and lived in the water.
⁷
Those first photosynthetic organisms therefore weren’t plants as we know them today but single-celled algae, like those that make up the mat you might see on the surface of a polluted pond, for example. Many kinds of single-celled algae are still around today, but one lineage of algae has changed a lot since then, becoming multicellular, adapting to life on land, and becoming the plants we know and love. (In other words, plants are specialized kinds of algae.)

Plants and algae can photosynthesize because they’re direct descendants of those first photosynthetic organisms and have inherited the complex machinery required to harness the sun’s energy. Animals can’t photosynthesize because they don’t have the
equipment. The idea that Prahlad Jani suddenly just happened to be able to make sugars from sunlight would be like discovering one day that a brick factory could suddenly make sports cars.

You can’t harness the power of the sun by closing your eyes and having warm thoughts. It’s a precise chemical process. Photosynthesis requires dozens of incredibly specialized proteins that humans don’t have, all working together in perfect synchrony, like robots on a microscopic assembly line. A beam of sunlight penetrates the surface of a leaf, exciting a special molecule inside it, called chlorophyll a. Left alone, that excited molecule would give off some of that energy as light, glowing red as the energy dissipated. But in the leaf, it doesn’t glow, because crowds of orderly proteins around that molecule immediately jump into action, harnessing its energy to rip molecules of water (H
₂
O) and carbon dioxide (CO
₂
) apart, then rebuild their constituent atoms to make sugars (C
₆
H
₁₂
O
₆
).

Oxygen (O
₂
) molecules, by the way, are released from this process as a waste by-product, the result of the plant’s having extra O
₂
left over from the breakdown of the H
₂
O and CO
₂
. But one life form’s trash is another life form’s treasure: oxygen is a waste product we’ve built our lives on. (More about that in the chapter on wrath.)

Have you ever played with those halves of hollow rubber balls that you can flip inside out and then place on a table, until a few seconds later they spontaneously pop back into their previous shape and go flying into the air? That’s how I like to think of sugars. It takes energy to bend a half ball into that inverted shape, and that energy is physically stored within the structure of the half ball itself. When the half ball pops, the energy is released as the object relaxes to a more “comfortable” shape. Sugars basically
work just like that. It takes energy for a plant to load atoms into a sugar, and that energy can sit there, inside the sugar, to be released later on. When a sugar is broken back down to water and carbon dioxide, the energy comes popping out. Plants build sugars so they can use the sun’s energy later on—for growth, reproduction, and whatever other processes are required for staying alive. But if an animal steals a sugar by eating part of a plant, the animal can break the sugar down itself and use the energy for its own purposes.