‘There are two major theories about how to stop aging,’ Varya says. ‘The first is that you should suppress the reproductive system.’

‘The reproductive system,’ repeats Luke. His head is bowed over a small black notebook, which he brought today in addition to the tape recorder.

Varya nods. She met Luke in the atrium this morning, and now he follows her down the dirt trail to the primate lab. ‘A biologist named Thomas Kirkwood suggested that we sacrifice ourselves in order to pass genes along to our offspring, and that tissues with no role in reproduction – the brain, for example; the heart – endure damage in order to protect the reproductive organs. This has been proven in the lab: there are two cells in worms that give rise to its entire reproductive system, and when you use a laser to destroy them, the worm lives sixty percent longer.’

A pause before she hears Luke’s voice behind her. ‘And the second theory?’

‘The second theory is that you should suppress caloric intake.’ She punches a new key code – Annie changed it last night – into the pad beside the door with the knuckle of her right pointer finger. ‘Which is what I’m doing.’

The light turns green, and Varya opens the door as it beeps. Inside, she nods hello to Clyde and glances at the marmosets – today, all nine of them lie in the same hammock, indistinguishable except for their small metal tags – while using her elbow to press the elevator button for the second floor.

‘And that works how?’ asks Luke.

‘We think it has to do with a gene called DAF-16, which is involved in the molecular signaling pathway initiated by the insulin receptor.’ The door opens, and out walks an animal technician in blue scrubs; Varya and Luke take her place. ‘When you block this pathway in C. elegans, for instance, you can more than double its life span.’

Luke looks at her. ‘In English?’

Rarely does Varya discuss her work with non-scientists. All the more reason to take this interview, said Annie: to bring their work to the Chronicle’s wide audience.

‘I’ll give you an example,’ she says as the elevator door opens. ‘The people of Okinawa have the highest life expectancy in the world. I studied the Okinawan diet in graduate school and what’s clear is that while it’s very nutritious, it’s also very low in calories.’ She turns left, into a long hallway. ‘We eat food to produce energy. But energy production also creates chemicals that harm the body, because they cause cells to become stressed. Now, here’s the interesting part: when you’re on a restricted diet, like the Okinawans, you’re actually causing the system more stress. But this is what allows the body to live longer: it’s continuously dealing with a low level of stress, and this teaches it how to deal with stress in the long-term.’

‘It doesn’t sound very enjoyable.’ Luke wears a pair of technical pants with a zip-up hoodie. A pair of sunglasses is stuck in his hair, held in place by the curls.

Varya fits her key in the office door and pushes it open with her hip. ‘Hedonists don’t tend to live very long.’

‘But they have fun while they’re doing it.’ Luke follows her into the office. Her side is immaculate, while Annie’s is littered with PowerBar wrappers and water bottles and disheveled stacks of academic journals. ‘It sounds like you’re saying we can choose to live. Or we can choose to survive.’

Varya hands him a stack of facility clothing. ‘Protective gear.’

He takes the bundle in his arms and sets his backpack down. The pants are almost too short; Luke’s legs are long and thin, and without warning Varya sees Daniel’s legs, Daniel’s face. She turns away from him to steady herself. For years after his death, she had no episodes at all. But one Monday, four months ago, her coffeemaker broke, so she went to Peet’s and stood in a long line of customers. The music was hideous – a jazzy Christmas compilation, though it was barely Thanksgiving – and something about this and the crowds and the dense, suppressive smell of coffee grinding and the accompanying screech made Varya feel as though she were choking. By the time she reached the cashier, she could see that the employee’s mouth was moving but she could not hear what it said. She stared, watching the mouth as if from one end of a telescope, until it spoke more sharply – ‘Ma’am? Are you all right?’ – and the telescope clattered to the ground.

When she turns around, Luke is already suited up, and he is staring at her.

‘How long have you been working here?’ he asks, which is different than what she thought he would say – Are you all right? – and for this she is grateful.

‘Ten years.’

‘And before that?’

Varya crouches to slip on her shoe covers. ‘I’m sure you’ve done your research.’

‘You graduated from Vassar with your BS in 1978. By 1983 you were in graduate school at NYU, which you finished in ’88. You stayed on as a research assistant for another two years, and then you took a fellowship at Columbia. In ’93 you published a study on yeast – “Extreme life span extension in yeast mutants: age-dependent mutations increase at slower pace in organisms with CR-activated Sir2,” if I’m not mistaken – which was groundbreaking enough to be covered by some of the popular science magazines, and then the Times.’

Varya stands, surprised. The information he’s cited is available on the Drake’s website, but she had not given him so much credit as to expect he had it memorized.

‘I wanted to make sure I had my facts straight,’ Luke adds. His voice is muffled by the mask, but his eyes, as seen through the face shield, look slightly sheepish.

‘You do.’

‘So why the leap to primates?’ He holds the office door open for her, and she locks it from the outside.

She had been used to organisms so tiny they could only be properly viewed through a microscope: laboratory yeast, shipped in vacuum-sealed containers from a supply company in North Carolina, and fruit flies bred for human study, with miniature wings too small for flight. Varya was forty-four when the Drake’s CEO – then a stern older woman who warned Varya that an opportunity like this would not come her way again – invited her to run a caloric-restriction study in primates. When they hung up, Varya laughed in fear. She had enough trouble going to the doctor’s office; to spend her days in close proximity to rhesus monkeys, from which she could catch tuberculosis and herpes B, was inconceivable.

What’s more, she was baffled. She hadn’t worked with primates, or even with mice, but this, said the CEO, was the source of their interest: the Drake wanted not to promote a low-calorie lifestyle for human beings – ‘Imagine how successful that would be,’ the woman said, wryly – but to develop a drug that would have the same effect. They needed someone who was well versed in genetics, someone who could analyze their findings on a molecular level. And she was quick to assure Varya that her daily tasks would have little to do with the animals. They had technicians and a veterinarian for that. Most of Varya’s time would be spent on conference calls, in meetings, or at her desk: reading and reviewing papers, writing grants, assessing data, preparing presentations. Really, if she preferred, she could have no contact with the animals at all.

Now Varya leads Luke toward a large steel door. ‘We share about ninety-three percent of our genes with rhesus monkeys. I was more comfortable working with yeast. But I realized that what I was doing with yeast would never matter as much to human beings – could never matter as much, biologically speaking – as a study in primates.’

What she does not say is that the year 2000, when she was approached by the Drake, was almost ten years after Klara’s death and twenty after Simon’s. ‘Think about it,’ the CEO said, and Varya said she would, while calculating how much time would reasonably pass if she were to do such a thing so that she knew how long to wait before declining. But when she returned to her lab at Columbia, where she was running a new study on yeast, she felt not satisfaction or pride but worthlessness. When Varya was in graduate school, her research had been groundbreaking, but these days, any postdoc knew how to extend the life span of a fly or a worm. In five years, what would she have to show for herself? Likely no partner, certainly no children, but this, ideally: a major finding. A different sort of contribution to the world.

She took the job for another reason, too. Varya had always told herself that she did her research out of love – love for life, for science, and for her siblings, who hadn’t lived long enough to reach old age – but at heart, she worried that her primary motivation was fear. Fear that she had no control, that life slipped through one’s fingers no matter what. Fear that Simon and Klara and Daniel had, at least, lived in the world, while Varya lived in her research, in her books, in her head. The job at the Drake felt like her last chance. If she could push herself to do this, in spite of what misery it would cause her, she could chip away at her guilt, that debt her survival had engendered.

‘Your gloves,’ she says, stopping outside the door to the vivarium. ‘Don’t take them off, either pair.’

Luke holds up his hands. His camera hangs around his neck from a strap; he’s left his notebook and tape recorder in the office. Varya opens the rubber-sealed door of Vivarium 1, another door opened only by a key code that Annie changes each month, and leads Luke into the blinding midday roar.

Vivarium, in Latin, means ‘place of life.’ In science it refers to an enclosure where living animals are kept in conditions that simulate their natural environment. What is the natural environment of the rhesus monkey? Human beings are the only primate more broadly distributed across the globe than the rhesus macaque, these nomads who have traveled across land and over water, who can live as well on a four-thousand-foot mountain as in a tropical forest or a mangrove swamp. From Puerto Rico to Afghanistan the monkey thrives, making homes of temples and canal banks and railway stations. They eat insects and leaves along with what food they can scavenge from humans: fried bread, peanuts, bananas, ice cream. Every day, they travel miles.

None of this is easy to simulate in the lab, but the Drake has tried. Because macaques are social creatures, they are caged in pairs, and each cage has the ability to open up into the next, creating a column the width of the vivarium. Enrichment activities ensure that the monkeys are stimulated: psychologically, via the puzzle feeders and mirrors as well as plastic balls and videos viewed on iPads (though recently the iPads were removed because the monkeys so frequently broke the screens) and jungle sounds played through overhead speakers. The lab is visited annually by a representative from the federal Department of Agriculture, who ensures their compliance with the Animal Welfare Act, and last year this person recommended that staff occasionally enter the vivarium wearing different clothing – hats or gloves in exciting patterns – to intrigue and entertain the animals, which they now do as well.

Varya is not deluded. Of course, the monkeys would rather be outdoors. Behind the vivarium is a larger caged area where the monkeys can play with tires or ropes and swing on netting, though in truth it should be larger, and each monkey receives only a couple of hours there each week. But the point is that her study seeks not to test new drugs or research SIV but to keep the animals alive for as long as possible. Where is the fault in that?

She turns to Luke and shares the talking points that Annie prepared. Without primate research, countless viruses would not have been discovered. Countless vaccines would not have been developed, and countless therapies would not have been proven safe for Alzheimer’s, Parkinson’s, and AIDS. Then there is the fact that life in the outside world is no picnic, full of predators and potential starvation. Nobody but a sadist, and perhaps Harry Harlow, likes the sight of a monkey in a cage, but at least, at the Drake, they are cared for and protected.

Still, she can see how a visitor could get the wrong impression. The cages are stacked against the walls, leaving a narrow center aisle for Varya and Luke. The animals face them, splayed against the mesh like geckos. Their pink bellies are stretched long, fingers hooked through the open squares. The dominant monkeys stare silently with their mouths open and their long, yellow teeth bared; the less dominant ones grimace and scream. They do the same thing to the Drake’s new CEO, a man who visits the lab once or twice a year for as little time as possible.

In her first year, the monkeys also reacted this way to Varya. It took all her self-control not to flee. But she did not flee, and though the former CEO had been right – most of Varya’s time is spent at her desk – she forces herself to visit the vivarium once daily, usually to administer breakfast. She does not touch the animals, but she likes to know how they are doing, likes to see the evidence of her success. She brings Luke’s attention to the calorie-restricted monkeys and then to the control monkeys, who eat as much as they please. Luke takes photos of each group. The flash makes them scream louder. Some of the monkeys have begun to shake the bars of their cages, so Varya shouts to explain that the controls are more prone to early-onset diabetes and that their risk of disease is almost three times higher than that of the restricted group. The restricted group even looks younger: their oldest members have lush, auburn fur while the controls are wrinkled and balding, their red rumps showing through.

This is the midpoint of the study, so it’s too soon to assess total life span. Still, it’s clear that the results are promising, that they suggest Varya’s thesis is likely to be proven, and in sharing this she feels such pride that she can ignore the screaming, the scrabbling, the scent, and face the monkeys, her subjects, with pleasure.

When Luke has left, she retrieves Frida.

Earlier today, she asked Annie to move her into the isolation chamber. Frida is her favorite monkey, but Frida is bad PR – Frida of the broad, flat brow, her golden eyes rimmed in black as if by kohl. As a baby, her ears were overlarge, her fingers long and pink. She arrived in California one week after Varya herself. That morning, Annie had received a shipment of new monkeys, but there was one held up due to a snowstorm, a baby who had been bred at a research center in Georgia. Annie had to leave, so Varya stayed. At nine thirty p.m. an unmarked white van trundled up the hill and stopped outside of the primate lab. Out climbed an unshaven boy who couldn’t have been more than twenty and who had Varya sign a receipt, as if for a pizza. He seemed to have no interest in his cargo, or perhaps he had grown sick of it: when he retrieved the cage, which was covered by a blanket, it emitted such horrible screeching that Varya instinctively backed away.

But the animal was her responsibility now. She wore full protective clothing, though this did nothing to dim the sounds that came from the cage as the driver handed it over. He wiped his face with relief and jogged back to the van. Then he drove down the hill far faster than he had driven up, leaving Varya and the screaming cage alone.

The cage was the size of a microwave. They would not introduce Frida to the other animals until tomorrow, so Varya brought the cage to an isolated room the size of a janitor’s closet, and set it down. Her arms were already aching and her heartbeat flapped with terror. Why had she ever agreed to this? She had not even done the hardest part, which was the physical transition from old cage to new, and which required Varya to touch the animal inside.

The cage was still covered by what Varya now saw was a baby blanket, patterned with yellow rattles. She peeled back a corner of the blanket, and the animal’s cries grew louder. Varya sat back on her heels. Her anxiety was ballooning – she knew she had to do the transition now or she would not be able to do it at all – so she hefted the small transport cage until its opening aligned with the door of the lab cage. Inhaling she removed the blanket. The carrier was barely bigger than the monkey itself, but the animal began to revolve, turning circles while grasping the bars. Varya reached for the lock as Annie had shown her, but her hands shook – the monkey’s confusion and fear were unbearable – and before she could steady herself, the carrier slid to one side.

Out shot the baby, as if from a cannon. It did not land in the larger cage but on Varya’s chest. She could not help it: she screamed, too, and fell back from her knees to her rear. She thought the monkey meant to hurt her, but it wrapped its slender arms around her back and clung, pressing its face to her breast.

Who was more terrified? Varya had images of amebiasis and hepatitis B, all the diseases of which she dreamed nightly and feared she would die, all the reasons she had not wanted to take this job in the first place. But pressing back against that fear was another living creature. The baby’s body was heavy, so much denser than a human baby’s that it made the latter seem hollow. She did not know how long they stayed that way, Varya rocking back on her heels as the monkey cried. It was three weeks old. Varya knew it had been taken from its mother at two weeks, that it was the mother’s first child, and that the mother, whose name was Songlin – she had been transported from a breeding center in Guangxi, China – had been so distressed that she was tranquilized in the midst of that process.

At one point she looked up and saw their reflection in the mirror mounted to the outside of the cage. What came to her then was Frida Kahlo’s Self-Portrait with Monkey. Varya did not look like Kahlo – she was not as strong, she was not as defiant – and the lab, with its beige concrete walls, could not be further from Kahlo’s yucca and large, glossy leaves. But there was the monkey in Varya’s arms, her eyes dark and enormous as blackberries; there were the two of them, equally fearful, equally alone, staring into the mirror together.