Katherine J. Wu

On the list of perfect pet parents, Mikel Delgado, a professional feline-behavior consultant, probably ranks high. The Ph.D. expert in animal cognition spends half an hour each evening playing with her three torbie cats, Ruby, Coriander, and Professor Scribbles. She’s trained them to take pills in gelatin capsules, just in case they eventually need meds. She even commissioned a screened-in backyard catio so that the girls can safely venture outside.

Nothing gets a female mosquito going quite like the stench of human BO. The chase can begin from more than 100 feet away, with a plume of breath that wafts carbon dioxide onto the nubby sensory organ atop the insect’s mouth. Her senses snared, she flies person-ward, until her antennae start to buzz with the pungent perfume of skin. Lured closer still, she homes in on her host’s body heat, then touches down on a landing pad of flesh that she can taste with her legs.

Deep in the loamy soil of forests around the world, there exists a fungus called the honey mushroom that makes its living on death. A parasite that preys on weak trees, it sucks its victims dry of nutrients, then feasts on their postmortem flesh. Orchards and vineyards have fallen to it; gardeners, farmers, and foresters spend their days fruitlessly fighting the pesticide-resistant scourge.

Once again, the United States is messing up its approach to vaccines. Three months into its monkeypox outbreak, just 620,000 doses of the two-injection Jynneos shot—the nation’s current best immune defense against the virus—have been shipped to states, not nearly enough to immunize the 1.6 million to 1.7 million Americans that the CDC considers at highest risk. The next deliveries from the manufacturer aren’t slated until September at the earliest.

Today’s most elderly bats aren’t supposed to exist. Ounce for ounce and pound for pound, they are categorically teeny mammals; according to the evolutionary rules that hold across species, they should be short-lived, like other small-bodied creatures.And yet, many of Earth’s winged mammals buck this trend, sometimes blowing decades past their anticipated expiration date.

Seventy-eight days and more than 7,000 documented cases into the United States’s 2022 outbreak of monkeypox, federal officials have declared the disease a nationwide public-health emergency. With COVID-19 (you know, the other ongoing viral public-health emergency) still very much raging, the U.S. is officially in the midst of two infectious-disease crises, and must now, with limited funds, wrangle both at once.

In the 1980s, shortly before I was born, my father killed a male white-tailed deer in the woods of Oklahoma, harvested his flesh, and mounted his head. Years later, my brothers regaled me with the tale of Tony, as they posthumously named the buck. “Dad shot him,” they told me, with glee. “And then he made us eat him.” I hated the circumstances of Tony’s death. But I was also entranced.

When the monkeypox outbreak was first detected in the United States, it seemed, as far as infectious-disease epidemics go, like one this country should be able to handle. Tests and antivirals for the virus already existed; the government had stockpiled vaccines. Unlike SARS-CoV-2, monkeypox was a known entity, a relative softball on the pathogenic field.

And there it is: President Joe Biden has tested positive for the coronavirus, the White House announced Thursday morning, and is dosing up with Paxlovid to keep his so-far “very mild symptoms” from turning severe.In some ways, this is one of the cases the entire world has been waiting for—not sadistically, necessarily, but simply because, like so many other infections as of late, it has felt inevitable.

Among spiders, sex doesn’t just create life; it can also end it. Males of many species—including orb-weaving spiders, widow spiders, and wolf spiders—find their fortunes turning on a dime, as the females they’ve seduced begin to devour them alive, sometimes even before insemination is complete.

Not so long ago, America’s next COVID fall looked almost tidy. Sure, cases might rise as the weather chills and dries, and people flock indoors. But Pfizer and Moderna were already cooking up America’s very first retooled COVID vaccines, better matched to Omicron and its offshoots, and a new inoculation campaign was brewing.

Of all the eyeballs in Glen Jeffery’s office, only a very small minority are his.“Oh, I’ve got an office full of eyes,” Jeffery, a neuroscientist at University College London, told me. Over Skype, he fished one of his favorites out of an opaque vial: About the size of a golf ball and fringed with white tissue, it looked a bit like a poached egg with a slate-hued yolk.

In one sense, this is how it was always supposed to go: When viruses evolve, vaccines should follow, and sometimes try to leap ahead. The COVID-19 shots that the U.S. has used to inoculate hundreds of millions of people are simply so new that they’ve never had to undergo a metamorphosis; up until now, their original-recipe ingredients have stood up to SARS-CoV-2 well enough. But the virus they fight has changed quite radically, and this fall, the vaccines will finally, finally follow suit.

In the summer of 2003, just weeks after an outbreak of monkeypox sickened about 70 people across the Midwest, Mark Slifka visited “the super-spreader,” he told me, “who infected half of Wisconsin’s cases.”Chewy, a prairie dog, had by that point succumbed to the disease, which he’d almost certainly caught in an exotic-animal facility that he’d shared with infected pouched rats from Ghana.

Two years ago, Juan Díaz Ricaurte was hiking through the mountains of Brazil when a male yellow cururu toad affixed itself to his boot. Díaz Ricaurte gently detached the frog and set it back on the ground, several feet away; undeterred, it bounded back over and wrapped its arms around the shoe again. “It was super focused on grabbing Juan’s boot,” says Filipe Serrano, Díaz Ricaurte’s fellow biologist, who witnessed the meet-cute.

Updated at 2:55 p.m. on May 10, 2022In the two years since she caught the coronavirus, 38-year-old Jessica McGovern has cycled through “well over 100 drugs, supplements, and therapies” to try to keep her long-COVID symptoms at bay.

After four decades of training and studying dogs, Marjie Alonso has lost track of the number of pets she’s seen because their humans felt they weren’t acting as they “should.” There were the golden retrievers who weren’t “friendly” or “good enough with kids,” and the German shepherds who were more timid scaredy-cats than vigilant guard dogs.

Almost exactly 12 months ago, America’s pandemic curve hit a pivot point. Case counts peaked—and then dipped, and dipped, and dipped, on a slow but sure grade, until, somewhere around the end of May, the numbers flattened and settled, for several brief, wonderful weeks, into their lowest nadir so far.I refuse to use the term hot vax summer (oops, just did), but its sentiment isn’t exactly wrong.

In naked-mole-rat societies, the royals do not wield scepters or don crowns. But that’s not to say that their majesty is subtle. The toothy, pruney rodents live in close-knit underground communities of up to about 300 members apiece, ruled by a tyrant queen that refuses to be mistaken for just another balding pleb.

If the United States has been riding a COVID-19 ’coaster for the past two-plus years, New York and a flush of states in the Northeast have consistently been seated in the train’s front car. And right now, in those parts of the country, coronavirus cases are, once again, going up. The rest of America may soon follow, now that BA.2—the more annoying, faster-spreading sister of the original Omicron variant, BA.

Last Friday, Lakshmi Ganapathi’s son turned 5, and finally became eligible for his first Pfizer COVID shot. Ganapathi’s family had been anticipating that moment for more than a year, yet as of late, she can’t help but feel the slightest bit deflated. At first, the COVID vaccines’ trickle down the age brackets felt worth the wait because the shots were doing such a stellar job at blocking symptoms.

When a boa constrictor coils its midriff around a wriggling rat, it’s easy to feel sorry for the soon-to-be-lifeless rodent, its blood supply so blocked that its heart stops pumping.But consider, too, the plight of the snake. The curly-fry crush of a boa—which can exert pressures of up to 25 pounds per square inch—doesn’t just squish the life out of its prey.

At this very moment, the United States, as a whole, remains in its legit pandemic lull. Coronavirus case counts and hospitalizations are lower than they’ve been since last summer. There’s now a nice, chonky gap between us and January’s Omicron peak.And yet. Outbreaks have erupted across Asia.

About 18 years ago, while delivering a talk at a CDC conference, Gregory Poland punked 2,000 of his fellow scientists. Ten minutes into his lecture, a member of the audience, under Poland’s instruction, raced up to the podium with a slip of paper. Poland skimmed the note and looked up, stony-faced. “Colleagues, I am unsure of what to say,” he said. “We have just been notified of a virus that’s been detected in the U.S.

For male Santa Marta harlequin toads, sex is an exercise in patience.The ping-pong-ball-size frogs, which are native to a mountainous strip in northern Colombia, spend most of their days milling about the region’s burbling brooks, hoping to chance upon a mate. They don’t often get lucky: Only rarely, for a few days a year around the start of the rainy season, will the species’ much-larger females venture down from the trees to flit through these loose froggy frats.

The world was slow to recognize long COVID as one of the most serious consequences of the coronavirus. Six months into the pathogen’s tear across the globe, SARS-CoV-2 was still considered an acute airway infection that would spark a weeks-long illness at most; anyone who experienced symptoms for longer could be expected to be dismissed by droves of doctors.

If the coronavirus has one singular goal—repeatedly infecting us—it’s only gotten better at realizing it, from Alpha to Delta to Omicron. And it is nowhere near done. “Omicron is not the worst thing we could have imagined,” says Jemma Geoghegan, an evolutionary virologist at the University of Otago, in New Zealand. Somewhere out there, a Rho, a Tau, or maybe even an Omega is already in the works.Not all variants, though, are built the same.

And just like that, the national attitude on COVID is flipping like a light switch. As the United States descends the bumpy back end of the Omicron wave, governors and mayors up and down the coasts are extinguishing indoor mask mandates and pulling back proof-of-vaccination protocols.

In many ways, the pandemic has never felt quite so paradoxical. In the United States, cases and hospitalizations are falling, and millions of people are as vaccinated as they can be. A rash of coastal-state mayors and governors is peeling back mask mandates—a stateside mirror of countries such as Denmark, Sweden, and Norway, where pandemic restrictions have all but disappeared. Things are definitively better than they were just a few weeks ago.

When researchers consider the classic five categories of taste—sweet, salty, sour, bitter, and umami—there’s little disagreement over which of them is the least understood. Creatures crave sweet for sugar and calories. A yen for umami, or savoriness, keeps many animals nourished with protein. Salt’s essential for bodies to stay in fluid balance, and for nerve cells to signal. And a sensitivity to bitterness can come in handy with the whole not-poisoning-yourself thing.