One of the most frequent complaints of orbital crew members is insomnia; they pop sleeping pills on a regular basis and still get only about six hours of shuteye, though they’re allotted eight. Steven W. Lockley, a Harvard neuroscientist, recommends altering the light to improve matters. In 2012 he advised NASA engineers to change the light bulbs on the International Space Station to a type of LED that can display blueshifted light during the “day,” when the crew is working, and redshifted light when they need to rest. Why the difference? That crucial ganglion, the circadian photoreceptor, is particularly sensitive to light toward the bluish end of the red, orange, yellow, green, blue, indigo, and violet visible-light spectrum.
Blue light also pours from the phone, tablet, or computer screen on which you’re reading this. This light, in a wavelength very similar to daylight, has been shown to exacerbate insomnia in scores of studies. In 2007 Belgian researchers surveyed 1,656 teenagers about their use of mobile phones after lights-out and found that those who used a phone less than once per week were more than twice as likely to be “very tired” a year later as those who never did. Using a phone after lights-out about once a week increased the risk of being “very tired” by five times. In 2012 researchers at Rensselaer Polytechnic Institute showed that two hours of exposure to a bright tablet screen at night, like an iPad or a Kindle, reduced melatonin levels by 22 percent. And the National Sleep Foundation says that more than 90 percent of Americans regularly use some type of electronic device in the hour before bed.
There is a great difference between natural night waking and electronic-induced insomnia, Stevens points out. In his history of the night, Ekirch explains that temporary nighttime waking—of the type that used to plague Stevens—is hardly unnatural. Humans have aroused in the middle of the night since time immemorial to pee, snack, chat with relatives and neighbors, make love, and simply enjoy “quiet wakefulness.” “There is every reason to believe that segmented sleep, such as many wild animals exhibit, had long been the natural pattern of our slumber before the modern age, with a provenance as old as humankind,” Ekirch writes. The unnatural part is that now we get up and we turn on the light, silencing melatonin.
Insomnia is hardly the worst side effect of light pollution. Shift workers, who rise with the night and work awash in blue light, experience not only disrupted circadian rhythms and sleep deprivation but an increased risk of breast and prostate cancer. These cancers, which require hormones to grow, are suppressed in the presence of melatonin, Stevens has shown. In 2010 Stevens published a review of breast cancer sensitivity in 164 countries and found a 30 to 50 percent increased risk of cancer in nations with the worst light pollution, but no increased prevalence of non-hormonally dependent cancers in the same populations.
“Our use of electric light in the modern world is disrupting our circadian sleep and our biology. There is no question about that. Does that have physiological consequences? There is more and more evidence that it does,” Stevens told me. “The epidemiological studies are the crudest but the most important.”
As we discussed a litany of light-related problems, I asked Stevens, “Is it a legitimate question to ask if light is the major factor in depression, obesity, and cancer? Is there potential for light to be the reason behind all of those things?”
“Yes,” he said flatly. “No doubt about it.” The day is coming when doctors might feel confident saying so, he added, just as they now say that smoking causes lung cancer. The murky part is what to do about it.
A torrent of light is what you might call a “First World problem.” Even as Western cities try to bring back starlit nights, students throughout developing countries in Southeast Asia and sub-Saharan Africa still read by candlelight. Economically depressed regions tend to be darker; after the collapse of communism, satellite imagery showed several countries in the former Soviet Union were dimmer at night.
When we in the industrialized world do manage to turn off the lights, there are measurable, beneficial effects on our circadian rhythms. In a widely reported paper last summer, Kenneth Wright at the University of Colorado at Boulder took eight students camping in the Rocky Mountains for two weeks. They weren’t allowed to use any artificial light after the sun went down—only the sanguine glow of campfire. After a week melatonin started to rise at sunset, peak in the middle of the night, and taper just at sunrise, which Wright called a “remarkable” result. “Internal biological time under natural light-dark conditions tightly synchronizes to environmental time, and in this regard, humans are comparable to other animals,” he wrote.
Of course, very few of us are going to camp outside nightly or stop working at 4:30 p.m. in winter, let alone shut down power plants and global commerce. And even as I mourn the loss of night, I am no Luddite myself. I read Wright’s study and so many others while sitting in bed, hours after the sun had set, bathed in the bluish spectrum of light emitted by my iPad. I am a nighttime chronotype and I drink electricity as thirstily as anyone.
But there are a few things we can all do.
As NASA has found, redshifted lamps, rather than a blue hue, are a better choice for bedside reading. Chronobiologists are concerned about the fluorescent swirls that will comprise the majority of American light fixtures when the ban on incandescent bulbs finally sets in. They emit too much blue light—we should use redshifted LEDs instead. The same goes for many building lights and streetlamps. Along with keeping us more awake, this light is especially intrusive for the same reason the sky is blue: it scatters more readily, causing even more light pollution.
Downward-directed streetlamps can illuminate larger areas while casting fewer shadows and errant upward glow. Smarter, more efficient use can cut wasted light, wasted money, and wasted energy. This has been a powerful factor in bringing back the night in towns from Brainerd, Minnesota, to Paris, the City of Light. Since July 2013 the French capital has been going dark for several hours at night to save money and “reduce the print of artificial lighting on the nocturnal environment,” in the words of its Environment Ministry. In a paper published this January, Exeter’s Jonathan Bennie and colleagues reported that some economically developed regions, especially throughout Europe, are trending darker.
For those of us addicted to our glowing phones and tablets, an app called F.lux can help. It “warms” your device’s display screen so that it shifts red in the evening, more closely matching incandescent bulbs and the hue of the setting sun. Just a brief glimpse at your mobile phone at bedtime is enough to expose your retinas to artificial light, so fighting such a comprehensive intrusion might be an exercise in futility. But even if we can’t completely quench our thirst for light, we can all make one small gesture, which could prompt us to unplug a little more.
I try to do this whenever the sky above St. Louis is clear. After I climb out of my car but before I open the fence gate and the hinge cheeps, before I step onto the deck and the wood sags and the motion-sensor light turns on, I stop, and I look up. I nod at Jupiter, blazing in the east. I greet Orion in his more familiar northern form. I squint at the moon if it is there and I let my eyes open wide, hoping more stars will leak through the city haze and reach me standing there, in the darkness.
ALISON HAWTHORNE DEMING
Spotted Hyena
FROM Orion
ON A DARK and moonless night of storms, Hans Kruuk observed a pack of spotted hyenas engaging in a predatory orgy of killing. The Dutch biologist had spent three and a half years living with Serengeti hyenas, documenting their complex matriarchal clan structure and cooperative hunting strategies and keeping a full-grown hyena named Solomon as a house pet. Hyenas make a living by scavenging and hunting. Their large jaw muscles and bone-crushing premolars give them chewing ability stronger than a brown bear’s. They eat and digest parts of dead animals other predators leave for waste, including bones. Their gut is so efficient that their feces are white and powdery. Hyenas rival primates in intelligence and skill at cooperative hunting. In captivity, pairs of hyenas,
given the challenge to pull two ropes in unison to get a food reward, learned the skill more quickly than chimps given the same task. They rivaled the chimps too in passing on the skill to inexperienced clan mates.
Spotted hyenas are weird-looking. Cute teddy-bear ears. Fluffy, mottled coat. The cantilevered stance, hind legs much shorter than forelegs, makes the animal look somehow taller than itself and always ready to lunge. There is menace in the darting eyes. Their whooping cry has earned them the nickname “laughing hyena,” though it sounds nothing like laughter except in bedlam. They live in clans of five to 90 members, led by an alpha female whose offspring will inherit her role. Aristotle thought hyenas resembled hermaphrodites. There is little sexual dimorphism in their genitalia. The female has a six-inch clitoris that can become erect. The labia are fused in a sac resembling a scrotum. This confusing equipment entered oral tradition as protoscience: in medieval bestiaries, the hyena was said to change its gender at will or with the season. For the female hyena, this gear means difficult childbirth, as the young emerge through the clitoris.
Kruuk observed that during a violent storm in Tanzania’s Ngorongoro Crater, a herd of Thompson gazelles became frenzied and disoriented. The hyenas became excited and gave chase, pursuing the gazelles with a zeal matching the storm’s intensity. They slaughtered 80 in a night—far more than the pack could possibly eat. He named the behavior “surplus killing,” and it is now known that many carnivores do this. It may be more likely to occur when predators are overstimulated and prey weakened by ill health or weather. Kruuk later reported that three crows went on a binge, caching 79 mice in slightly over two hours. Other reports of surplus killing tally red foxes in north Scotland killing 200 black-headed gulls in a night, and similar binges by minks feeding on terns, killer whales on seal pups, and even among spiders hunting flies. Surplus killing is not the norm, but it is common enough in the carnivorous world to say that the capacity for this behavior is a component of the animal spirit.
Surplus killing looks brutal and gratuitously violent to the human eye, though our species too is quite accomplished in acts that have earned those descriptors. But for an animal that must kill to live, it makes sense for the hunt and the kill to be pleasurable. If you don’t kill, you don’t eat, and if you don’t eat, you die. Nature’s clever trick is to make behaviors that enhance survival among a creature’s keenest pleasures: eating, having sex, maternal bonding, social cohesion. Animals engaged in surplus killing may simply be thrilling in their physical being—their skill and strength and muscular joy. Human beings add a new element to the repertoire of the animal spirit. In finding the behavior excessive, vicious, causing unnecessary suffering and death, humanity identifies itself as a creature holding values and making ethical judgments. Just because it feels good doesn’t mean you should do it.
I visited the Ngorongoro Crater in the company of two Peace Corps volunteers, a traveling companion, and a Chaga guide. My safari offered no opportunity for the sustained observation I so admire in a researcher of Kruuk’s dedication. What conclusions could I draw from a week of casual observation made through the roof of a Land Rover?
Surely not science. A casual observer can testify only to the moment. And what one sees will always be colored by what one longs to see. The unsettling truth is that most visitors to the last great animal spectacles on Earth long to see the kill. It thrills and arouses the imagination. It stimulates an atavistic hunger to live in a body so perfectly suited to meeting its needs. I saw no kill and counseled myself that I should not be disappointed.
Yes, I saw the dried pelt of a gazelle hanging from a baobab tree where a leopard had left it after supper. Yes, I saw the dismembered head of a zebra lying in scrub, the red gash where it had been severed as loud in mind today as when I saw it through the window of our racing microbus. But what struck me most keenly was the peace of the animals. Cloudlike herds of zebra, impala, and wildebeest drifted across Ngorongoro’s great grassy mind, shape-shifting throughout the afternoon. Two cheetahs trotted in purposeful single file toward the opening in the crater that leads to the Serengeti. The pride of lionesses lay on their backs in the high heat of the day, forelegs dawdling in the air. The black rhino slept, imitating a boulder in tall grass. The Egyptian goose and crown-crested cranes, Fischer’s lovebirds and superb starlings, hammerkops and saddle-billed storks dabbled in the shallows of wetlands or clawed up playful clouds of dust. The troop of baboons sat quietly under a sprawling tree, waiting out a rain squall. The peace of the land, the last islands of this peace, made me feel small. I welcomed the feeling. It was a pleasure to feel insignificant, to let my desires quiet, to feel, in the moment, the human body as an instrument attuned to peace.
SHERI FINK
Life, Death, and Grim Routine Fill the Day at a Liberian Ebola Clinic
FROM The New York Times
SUAKOKO, LIBERIA—The dirt road winds and dips, passes through a rubber plantation, and arrives up a hill, near the grounds of an old leper colony. The latest scourge, Ebola, is under assault here in a cluster of cobalt-blue buildings operated by an American charity, International Medical Corps. In the newly opened treatment center, Liberian workers and volunteers from abroad identify who is infected, save those they can, and try to halt the virus’s spread.
It is a place both ordinary and otherworldly. Young men who feel well enough run laps around the ward; acrid smoke wafts from a medical waste incinerator into the expansive tropical sky; doctors are unrecognizable in yellow protective suits; patients who may not have Ebola listen to a radio with those who do, separated by a fence and fresh air.
Here are the rhythms of a single day:
7:20 a.m.
Soon after their arrival, about a half-dozen doctors and nurses gathered near whiteboards for the handoff from the night shift. There were 22 patients, and no deaths overnight. The center—which includes a triage area, a restricted unit for patients suspected of having Ebola infections, and another for those in the grip of the disease—is not teeming like some clinics in Monrovia, more than four hours west. It is designed to accommodate up to 70 patients, but it is still scaling up after opening a few weeks ago and has just two ambulances to ferry patients.
An eight-year-old boy had been too weak to lift a liter bottle of oral rehydration solution to his mouth through the night. Bridget Anne Mulrooney, an American nurse, reported that she gave him a smaller bottle and sheets to keep warm. A woman who had lost both her baby and her husband to Ebola and was suspected of having the disease herself was refusing food and medications for symptoms and other possible illnesses, such as malaria. A man in his 70s, a talkative staff favorite, was now confused, his sheet covered in blood. He had been admitted four days earlier, but laboratory tests confirming an Ebola diagnosis had not come back yet. “I think he’s positive,” said Dr. Colin Bucks, an American. “I think this will be an end-of-life event.”
Eight patients needed intravenous fluids to combat dehydration. One patient was described as happy. Another was playing cards.
7:40 a.m.
Morning devotion began with a song and clapping, performed in triple time. About 18 local workers, most wearing rubber boots and blue hospital scrubs bleached so often that they were now pastel pink, danced and then prayed for God’s mercy on the treatment unit and those who worked there. Some folded their hands, sheathed in bright-colored gloves, at their heart. In unison the Liberians sang, “Cover with your protective arms, O God.”
8:10 a.m.
Sean Casey, an American who is the center’s team leader, gathered his department heads for what became a conversation about patient flow. The head of the ambulance crew said five patients with possible Ebola infections were awaiting rides to the center. But the ward with suspected cases was full, Mr. Casey said, and needed to be cleared first. Lab results were required, so patients without Ebola could be discharged and the confirmed cases could be moved to the other ward. The center also had some patients who were ill with other maladies. They should ha
ve been transferred to the local hospital, but it offered only limited care since reopening after six nurses died of Ebola.
The managers also discussed labor issues involving the 175-member Liberian staff, some of whom had walked out days before in one of the pay disputes common among the country’s health workers. The leaders and those who abandoned patient care would not be rehired, because it was crucial to have a dependable staff, Mr. Casey said. Then he sent everyone off.
“Go forward and do well,” Mr. Casey instructed.
8:40 a.m.
A Liberian woman scooped steaming yam porridge out of a blue bucket—breakfast for the patients and staff. The food is prepared off-site, at a university that is closed because of the outbreak and houses many of the staff members. The center has people working as cleaners, sprayers, and waste removers—part of the so-called WASH (water, sanitation, and hygiene) team—who continuously disinfect the site and remove contaminated material. Still, the sight was a little jarring: the woman was putting the food into plastic foam plates just a few steps from the dressing rooms for staff members coming out of the decontamination areas, the pharmacy, and past a refrigerator with a sign marked EBOLA BLOOD TESTS. NO FOOD.
8:45 a.m.
The Best American Science and Nature Writing 2015 Page 9