How scientists found an African bat lost to science for 40 years

Julius Nziza still remembers the moment vividly. Just before dawn on a chilly January morning in 2019, he and his team gently extracted a tiny brown bat from a net purposely strung to catch the nocturnal fliers. A moment later, the researchers’ whoops and hollers pierced the heavy mist blanketing Rwanda’s Nyungwe National Park. The team had just laid eyes on a Hill’s horseshoe bat (Rhinolophus hilli), which scientists hadn’t seen for nearly four decades.

Nziza, a wildlife veterinarian at Gorilla Doctors in Musanze, Rwanda, and a self-described “bat champion,” had been looking for the critically endangered R. hilli since 2013. For several years, Nziza and Paul Webala from Maasai Mara University in Narok, Kenya, with the help of Nyungwe park rangers, surveyed the forest for spots where the bats might frequent. They didn’t find R. hilli, but it helped them narrow where to keep looking.

In 2019, the team decided to concentrate on roughly four square kilometers in a high-elevation region of the forest where R. hilli had last been spotted in 1981. Accompanied by an international team of researchers, Nziza and Webala set out for a 10-day expedition in search of the elusive bat. It wasn’t rainy season yet, but the weather was already starting to turn. “It was very, very, very cold,” Nziza recalls.
Every night, from sunset until close to midnight, the researchers stretched nets across trails, where bats are most likely to fly, and kept watch. Then, after a few hours of rest, they woke early to check the traps again. It was cold enough that the bats could die if stuck too long.

At 4 a.m. on the fourth day, the researchers caught a bat with the distinctive horseshoe-shaped nose of all horseshoe bat species. But it looked slightly different from others they had captured. This one had darker fur and a pointed tip on its nose.

Everyone began shouting: “This is it!”
The researchers felt “almost 99 percent sure” they had found the lost bat. “We had a couple beers in the evening,” Nziza says. “It was worth celebration.” To be 100 percent sure, though, the team needed to compare its specimen to past ones of R. hilli. Fortunately, there were two in museums in Europe.

That’s because this isn’t the first time that R. hilli was lost, then found, to science. Victor van Cakenberghe, a retired taxonomist at the University of Antwerp in Belgium, rediscovered R. hilli 17 years after it was first seen in 1964. He says he still remembers finding the bat tangled in a mist net strung across a river. He kept the specimen and brought it back to a Belgian museum.

Nearly 40 years later, Nziza and colleagues compared the measurements of their bat, which was released into the wild, to the preserved bat. At long last, it can be confidently said that R. hilli was rediscovered again, researchers report March 11 in a preprint submitted to Biodiversity Data Journal.

And, for the first time ever, the scientists recorded R. hilli’s echolocation call. Now, the rangers can use acoustic detectors to keep an eye — or rather, an ear — on the bat (SN: 10/23/20). In nine months, they’ve already captured R. hilli calls from eight different locations in the same small area.
The team published its data to the open-access Global Biodiversity Information Facility in hopes of speeding up conservation efforts for the bat. Africa is home to over 20 percent of the world’s bats, but with a longstanding research focus on bats in Europe and the Americas, little is known about African bat species.

“It’s a whole new thing,” Nziza says. “That’s why everybody’s excited.”

‘Vagina Obscura’ shows how little is known about female biology

More than 2,000 years ago, Hippocrates, the Greek physician often considered the father of modern medicine, identified what came to be known as the clitoris, a “little pillar” of erectile tissue near the vagina’s entrance. Aristotle then noticed that the seemingly small structure was related to sexual pleasure.

Yet it wasn’t until 2005 that urologist Helen O’Connell uncovered that the “little pillar” was just the tip of the iceberg. The internal parts of the organ reach around the vagina and go into the pelvis, extending a network of nerves deeper than anatomists ever knew.

It took millennia to uncover the clitoris’s true extent because sexism has long stymied the study of female biology, science journalist Rachel E. Gross argues in her new book, Vagina Obscura. Esteemed men of science, from Charles Darwin to Sigmund Freud, viewed men as superior to women. To be male was to be the ideal standard. To be female was to be a stunted version of a human. The vagina, the ancient Greeks concluded, was merely a penis turned inside out, the ovaries simply interior testicles.

Because men mostly considered women’s bodies for their reproductive capabilities and interactions with penises, only recently have researchers begun to truly understand the full scope of female organs and tissues, Gross shows. That includes the basic biology of what “healthy” looks like in these parts of the body and their effects on the body as a whole.

Vagina Obscura itself was born out of Gross’ frustration at not understanding her own body in the wake of a vaginal infection. After antibiotics and antifungal treatments failed due to a misdiagnosis, her gynecologist prescribed another treatment. As Gross paraphrases, the doctor told her to “shove rat poison up my vagina.” The infection, it turned out, was bacterial vaginosis, a hard-to-treat, sometimes itchy and painful condition caused by an overgrowth of bacteria that normally reside in the vagina. (The rat poison was boric acid, which is also an antiseptic. “It’s basically rat poison,” the doctor said. “You’re going to see that on the internet, so I might as well tell you now.”)
The book’s exploration of female anatomy begins from the outside in, first traversing the clitoris’s nerve-filled external nub to the vagina, ovaries and uterus. The last chapter focuses on gender affirmation surgery, detailing how physicians have transformed the field for transgender people. (Gross is up-front that words such as women and men create an artificial binary, with seemingly more objective terms like “male” and “female” not performing much better in encompassing humankind’s diversity, including intersex and transgender people.)

Throughout this tour, Gross doesn’t shy away from confronting the sexism and prejudices behind controversial ideas about female biology, such as vaginal orgasms (versus coming from the clitoris) and the existence of the G-spot (SN: 4/25/12). Both “near-mystical” concepts stem from the male perspective that sexual pleasure should be straightforward for women, if only men could hit the right spot. Nor are the more appalling offenses swept under the rug, including racism, eugenics and female genital cutting. Footnotes throughout the book detail Gross’ efforts to navigate controversial views and stigmatizing or culturally charged terminology.

To lift readers’ spirits, she finds the right spots to deliver a dose of wry humor or a pun. She also shares stories of often forgotten researchers, such as lab technician Miriam Menkin, who showed in 1944 that in vitro fertilization is possible (SN: 8/12/44). Yet Menkin’s role in describing the first instance of a human egg being fertilized in a lab dish has largely been erased from IVF’s history (SN: 6/9/21). There’s also plenty of opportunity to marvel at the power of the female body. Despite the long-held notion that a person is born with all the eggs they’ll ever have, for example, researchers are now discovering the ovary’s regenerative properties.

Studying female bodies more closely could ultimately improve quality of life. Chasing cells capable of producing more eggs might bring about discoveries that could restore the menstrual cycle in cancer patients rendered infertile by chemotherapy or make menopause less miserable. Patients with endometriosis, a painful disorder in which uterine tissue grows outside the uterus, are often dismissed and their symptoms downplayed. Some doctors even recommend getting pregnant to avoid the pain. But people shouldn’t have to suffer just because they aren’t pregnant. Researchers just haven’t asked the right questions yet about the uterus or endometriosis, Gross argues.

Vagina Obscura reinforces that female bodies are more than “walking wombs” or “baby machines.” Understanding these organs and tissues is important for keeping the people who have them healthy. It will take a lot of vagina studies to overcome centuries of neglect, Gross writes. But the book provides a glimpse into what is possible when researchers (finally) pay attention.

Wally Broecker divined how the climate could suddenly shift

It was the mid-1980s, at a meeting in Switzerland, when Wally Broecker’s ears perked up. Scientist Hans Oeschger was describing an ice core drilled at a military radar station in southern Greenland. Layer by layer, the 2-kilometer-long core revealed what the climate there was like thousands of years ago. Climate shifts, inferred from the amounts of carbon dioxide and of a form of oxygen in the core, played out surprisingly quickly — within just a few decades. It seemed almost too fast to be true.

Broecker returned home, to Columbia University’s Lamont-Doherty Earth Observatory, and began wondering what could cause such dramatic shifts. Some of Oeschger’s data turned out to be incorrect, but the seed they planted in Broecker’s mind flowered — and ultimately changed the way scientists think about past and future climate.

A geochemist who studied the oceans, Broecker proposed that the shutdown of a major ocean circulation pattern, which he named the great ocean conveyor, could cause the North Atlantic climate to change abruptly. In the past, he argued, melting ice sheets released huge pulses of water into the North Atlantic, turning the water fresher and halting circulation patterns that rely on salty water. The result: a sudden atmospheric cooling that plunged the region, including Greenland, into a big chill. (In the 2004 movie The Day After Tomorrow, an overly dramatized oceanic shutdown coats the Statue of Liberty in ice.)
It was a leap of insight unprecedented for the time, when most researchers had yet to accept that climate could shift abruptly, much less ponder what might cause such shifts.

Broecker not only explained the changes seen in the Greenland ice core, he also went on to found a new field. He prodded, cajoled and brought together other scientists to study the entire climate system and how it could shift on a dime. “He was a really big thinker,” says Dorothy Peteet, a paleoclimatologist at NASA’s Goddard Institute for Space Studies in New York City who worked with Broecker for decades. “It was just his genuine curiosity about how the world worked.”

Broecker was born in 1931 into a fundamentalist family who believed the Earth was 6,000 years old, so he was not an obvious candidate to become a pathbreaking geoscientist. Because of his dyslexia, he relied on conversations and visual aids to soak up information. Throughout his life, he did not use computers, a linchpin of modern science, yet became an expert in radiocarbon dating. And, contrary to the siloing common in the sciences, he worked expansively to understand the oceans, the atmosphere, the land, and thus the entire Earth system.

By the 1970s, scientists knew that humans were pouring excess carbon dioxide into the atmosphere, through burning fossil fuels and cutting down carbon-storing forests, and that those changes were tinkering with Earth’s natural thermostat. Scientists knew that climate had changed in the past; geologic evidence over billions of years revealed hot or dry, cold or wet periods. But many scientists focused on long-term climate changes, paced by shifts in the way Earth rotates on its axis and circles the sun — both of which change the amount of sunlight the planet receives. A highly influential 1976 paper referred to these orbital shifts as the “pacemaker of the ice ages.”

Ice cores from Antarctica and Greenland changed the game. In 1969, Willi Dansgaard of the University of Copenhagen and colleagues reported results from a Greenland ice core covering the last 100,000 years. They found large, rapid fluctuations in oxygen-18 that suggested wild temperature swings. Climate could oscillate quickly, it seemed — but it took another Greenland ice core and more than a decade before Broecker had the idea that the shutdown of the great ocean conveyor system could be to blame.
Broecker proposed that such a shutdown was responsible for a known cold snap that started around 12,900 years ago. As the Earth began to emerge from its orbitally influenced ice age, water melted off the northern ice sheets and washed into the North Atlantic. Ocean circulation halted, plunging Europe into a sudden chill, he said. The period, which lasted just over a millennium, is known as the Younger Dryas after an Arctic flower that thrived during the cold snap. It was the last hurrah of the last ice age.

Evidence that an ocean conveyor shutdown could cause dramatic climate shifts soon piled up in Broecker’s favor. For instance, Peteet found evidence of rapid Younger Dryas cooling in bogs near New York City — thus establishing that the cooling was not just a European phenomenon but also extended to the other side of the Atlantic. Changes were real, widespread and fast.

By the late 1980s and early ’90s, there was enough evidence supporting abrupt climate change that two major projects — one European, one American — began to drill a pair of fresh cores into the Greenland ice sheet. Richard Alley, a geoscientist at Penn State, remembers working through the layers and documenting small climatic changes over thousands of years. “Then we hit the end of the Younger Dryas and it was like falling off a cliff,” he says. It was “a huge change after many small changes,” he says. “Breathtaking.”
The new Greenland cores cemented scientific recognition of abrupt climate change. Though the shutdown of the ocean conveyor could not explain all abrupt climate changes that had ever occurred, it showed how a single physical mechanism could trigger major planet-wide disruptions. It also opened discussions about how rapidly climate might change in the future.

Broecker, who died in 2019, spent his last decades exploring abrupt shifts that are already happening. He worked, for example, with billionaire Gary Comer, who during a yacht trip in 2001 was shocked by the shrinking of Arctic sea ice, to brainstorm new directions for climate research and climate solutions.

Broecker knew more than almost anyone about what might be coming. He often described Earth’s climate system as an angry beast that humans are poking with sticks. And one of his most famous papers was titled “Climatic change: Are we on the brink of a pronounced global warming?”

It was published in 1975.

Grainy ice cream is unpleasant. Plant-based nanocrystals might help

You can never have too much ice cream, but you can have too much ice in your ice cream. Adding plant-based nanocrystals to the frozen treat could help solve that problem, researchers reported March 20 at the American Chemical Society spring meeting in San Diego.

Ice cream contains tiny ice crystals that grow bigger when natural temperature fluctuations in the freezer cause them to melt and recrystallize. Stabilizers in ice cream — typically guar gum or locust bean gum — help inhibit crystal growth, but don’t completely stop it. And once ice crystals hit 50 micrometers in diameter, ice cream takes on an unpleasant, coarse, grainy texture.

Cellulose nanocrystals, or CNCs, which are derived from wood pulp, have properties similar to the gums, says Tao Wu, a food scientist at the University of Tennessee in Knoxville. They also share similarities with antifreeze proteins, produced by some animals to help them survive subzero temperatures. Antifreeze proteins work by binding to the surface of ice crystals, inhibiting growth more effectively than gums — but they are also extremely expensive. CNCs might work similarly to antifreeze proteins but at a fraction of the cost, Wu and his colleagues thought.

An experiment with a sucrose solution — a simplified ice cream proxy — and CNCs showed that after 24 hours, the ice crystals completely stopped growing. A week later, the ice crystals remained at 25 micrometers, well beneath the threshold of ice crystal crunchiness. In a similar experiment with guar gum, ice crystals grew to 50 micrometers in just three days.
“That by itself suggests that nanocrystals are a lot more potent than the gums,” says Richard Hartel, a food engineer at the University of Wisconsin–Madison, who was not involved in the research. If CNCs do function the same way as antifreeze proteins, they’re a promising alternative to current stabilizers, he says. But that still needs to be proven.

Until that happens, you continue to have a good excuse to eat your ice cream quickly: You wouldn’t want large ice crystals to form, after all.