Tag Archives: Animals

Minnesota’s lakes are running low on oxygen

This story originally featured on Nexus Media News, a nonprofit climate change news service.

On a sweltering morning in July of 2021, thousands of dead fish washed onto the northeastern shores of Pokegama Lake, 60 miles north of Minneapolis. 

Deb Vermeersch, an official with the Minnesota Department of Natural Resources, was called in to investigate. 

When she arrived, she saw a quarter-mile stretch of sand covered with the rotting carcass of walleye and Northern pike, which thrive in deep, cool waters, as well as crappies, sunfish and suckers—all warm water dwellers. “They were already pretty decomposed because of the warm water,” Vermeersch recalls. 

Because so many different types of fish had died, Vermeersch and her colleagues knew it wasn’t a species-specific parasite, a common cause of fish kills. They zeroed in on the culprit: dangerously low oxygen levels.

Oxygen is disappearing in freshwater lakes at a rate nine times that of oceans due to a combination of pollution and warming waters, according to a study published in Nature earlier this year. Lakes like Pokegama are warming earlier in the spring and staying warm into autumn, fueling algae blooms, which thrive in warm waters, and threaten native fish.

Minnesota, with its 14,380 lakes and temperatures that have risen faster than the national average, is a unique laboratory for studying how climate change is affecting temperate-zone lakes around the world. The state sits at the intersection of four biomes––two distinct prairie ecosystems and two ecologically different forest systems. This means scientists here are able to study how lakes in different ecosystems fare on a warming planet, and look for ways to stave off the worst effects of climate change. 

“If you start losing oxygen, you start losing species.

“What’s going on at the surface is that warmer water holds less oxygen than cool water,” says Lesley Knoll, a University of Minnesota limnologist and one of the authors of the Nature report. She says that longer, hotter summers are interfering with two key processes that have historically kept lakes’ oxygen levels in check: mixing and stratification. In temperate climates, water at the surface of lakes mixes with deep waters in the spring and the fall, when both layers are similar in temperature. As the surface water warms during the summer, the water forms distinct layers based on temperature––cool water at the bottom, warm at the top. This is known as stratification. In the fall, when the surface waters cool again, the water mixes for a second time, replenishing oxygen in deeper waters. But as climate change makes surface water warmer, and keeps it warmer for longer, that mixing doesn’t happen when it should.

“As you have that stronger stratification, the water in the deep part of the lake is cut off from the oxygen at the top part of the lake. If you start losing oxygen, you start losing species,” says Kevin Rose, a biologist at Rensselaer Polytechnic Institute in New York and a coauthor of the Nature study.

Knoll, Rose and a team of 43 other researchers studied 400 temperate lakes from around the world. They found that, on average, surface waters warmed by 7 degrees Fahrenheit and have lost roughly 5 percent of oxygen since 1980; deep waters, which haven’t warmed much, have still lost an average of almost 20 percent of their oxygen. (Thanks to the state’s long-held lake monitoring programs, almost a quarter the lakes in the study were in Minnesota.)

Warming lakes emit methane

Fish kills aren’t the only reason scientists are concerned about lakes losing oxygen. In extreme cases, when deep waters go completely void of oxygen, something else happens: Methane-emitting bacteria begin to thrive.

“As lakes warm, they will produce more methane and most of that has to do with stratification,” says James Cotner, a limnologist at the University of Minnesota.

Lakes normally emit carbon dioxide as a natural part of breaking down the trees, plants and animals that decay in them, but plants in and around fresh water also absorb it, making healthy lakes carbon sinks. 

Lakes have historically emitted methane, too––about 10 to 20 percent of the world’s emissions––but the prospect of them releasing more of the greenhouse gas has Cotner and his colleagues alarmed. Methane is about 25 times more potent than CO2 when it comes to trapping heat in Earth’s atmosphere.

Cotner is leading a team of researchers who are studying what conditions allow methane-emitting bacteria to prosper in lakes and how conservationists can respond. 

“The key questions are understanding how much and when carbon dioxide and methane are emitted from lakes, and what are the key variables that can tell how much will be emitted. Certainly, oxygen is a big part of that, but stratification and warming also plays a role,” says Cotner. 

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Pollution plays a big role

It’s not just longer, hotter summers that are causing lakes to lose their oxygen. Polluted agricultural runoff (pesticides and fertilizers) and logging have long plagued Minnesota’s lakes. It’s a problem that’s getting worse worldwide as climate change pushes agriculture further away from the equator and into new territory, says Heather Baird, an official with Minnesota’s Department of Natural Resources.

In northern Minnesota, potatoes now grow where pine forests have thrived for years. Phosphorus, a common fertilizer, now runs off from the soil into the region’s lakes, Baird says. Though small amounts of phosphorus occur naturally in lake ecosystems, too much of it feeds harmful algae blooms. 

Those blooms, which thrive in warm, nutrient-rich water, set off a chain of events that remove oxygen from deep lake waters.

“When phosphorus builds in lakes and creates algae blooms, those blooms eventually die. As they do, they sink. Deeper down, bacteria break down the algae, using up the remaining oxygen at those lower depths,” said Baird.

A quarter of Minnesota lakes now have phosphorus levels that are so high that the state advises against swimming, fishing or boating in them. Fueled by these nutrients, algae blooms take over, covering the lake in sometimes toxic residue that thrives in warm, nutrient-rich water, as was the case in Pokegama Lake earlier this year. The protists choke out aquatic life, especially fish that thrive in cold, deep waters. This is all exacerbated by warming air temperatures. 

The 75 percent rule

Researchers and conservationists in Minnesota are now studying the best ways to protect temperate-climate lakes from the worst effects of climate change. They have found that preserving 75 percent of deep-water lakes’ watersheds appear to keep fish stocks healthy. 

“Having a forested watershed helps keep better water quality by filtering out nutrients, which in turn can buffer against the impacts of climate change, to a point,” Knoll said. However, she added, as temperatures continue to rise, “that 75 percent may not be high enough anymore.” 

Knoll and state conservationists are focusing their research and efforts on deep, cool lakes that have a better chance of staying oxygenated than warmer, shallower lakes, like Pokegama.

July 2021, when the Pokegama Lake fish kill occurred, was the hottest month ever recorded on Earth. Parts of Minnesota were also experiencing the worst drought in 40 years, a trend some climatologists expect to persist in future summers. 

Vermeersch, the Minnesota fisheries supervisor, said it’s unclear what this will mean for the future of lakes like Pokegama. “Hopefully it’s not going to be a linear thing,” she said, adding that fish kills are “probably going to happen more often,” depending on a combination of factors. “When you get lakes like Pokegama that are shallow and already impaired, I think we are going to see more and more conditions like this.”

Correction (December 23, 2021): The story previously identified the wrong Pokegama Lake in Minnesota. The one that experienced the fish kill in July is 60 miles away from Minneapolis, not 140 miles away.

This fossilized dinosaur embryo is curled up just like a baby bird

Scientists have identified an extremely rare fossilized dinosaur embryo in an egg from southern China.

The late-Cretaceous specimen belongs to a group of dinosaurs called oviraptorosaurs, which are closely related to birds. Intriguingly, the embryo’s position resembles the “tucking” posture that modern birds assume before hatching. The findings indicate that this important adaptation evolved before birds split off from other dinosaurs, the researchers reported on December 21 in the journal iScience.

“Dinosaur embryos are key to the understanding of prehatching development and growth of dinosaurs,” Fion Waisum Ma, a PhD student in paleobiology at the University of Birmingham in the United Kingdom and coauthor of the findings, said in an email. While fossilized dinosaur eggs are abundant, however, embryos are much harder to come by. The dinosaur embryos that paleontologists have found are usually incomplete, with bones that have separated and become jumbled. 

By contrast, the newly described fossil includes an almost complete skeleton with bones arranged much as they were in life. “This little dinosaur is beautifully preserved in a fossilized egg,” Ma said. “We suspect the egg was buried by sand or mud quickly enough that it was not destroyed by processes like scavenging and erosion.”

She and her colleagues were able to reveal more than half the skeleton, with the rest still covered by rocky material in the egg. The fossil, originally discovered in an industrial park in China’s Jiangxi Province, dates to roughly 71 million to 65 million years ago. The elongated egg is 16.7 centimeters (6.6 inches) long and 7.6 centimeters (3 inches) wide, while the skeleton curled inside has a total length of 23.5 centimeters (9.3 inches).

[Related: A newfound South American dinosaur had a tail like a war club]

Oviraptorosaurs have been found in present-day North America and Asia. This dinosaur family is known for its diverse variety of skull shapes, including some with very tall crests. Had the embryo hatched, it probably would have grown into a medium-sized oviraptorosaur, Ma said, perhaps reaching 2 to 3 meters (6.6 to 9.8 feet) in length. The dinosaur would have been covered in feathers and had a toothless skull. 

The researchers compared the embryo’s anatomy with that of other oviraptorosaurs and theropods, the broader category of carnivorous dinosaurs that also includes Tyrannosaurus rex. The researchers also examined a fine slice of eggshell under the microscope and analyzed the evolutionary relationships among oviraptorosaurs to determine where the new embryo fell on the family tree. They concluded that the embryo belonged to a subgroup of oviraptorosaurs called Oviraptoridae. 

“The most surprising observation is the posture of this specimen—its body is curled with the back facing the blunt end of the egg, [and] the head below the body with the feet on each side,” Ma said. “This posture has never been recognized in a dinosaur embryo, but it is similar to a close-to-hatching modern bird embryo.”

This fossilized dinosaur embryo is curled up just like a baby bird
An artist’s reconstruction of the baby oviraptorid within its egg. Julius Csotonyi

To prepare for hatching, bird embryos reposition themselves in a process known as tucking. The oviraptorid fossil Ma and her team examined is arranged much like a 17-day-old chicken embryo in the first, or pre-tucking, phase. Over the next three days, a chicken embryo would gradually move into the final tucking posture, in which the body is curled with the head under the right wing. This posture seems to stabilize and direct the head while the bird cracks the eggshell with its beak, Ma said.    

She and her colleagues suspect that several previously discovered oviraptorid embryos are also arranged in various phases of tucking, although it’s hard to be certain because those specimens aren’t as well-preserved. Still, the team concluded that oviraptorids and modern birds may have used a similar strategy to maximize their chances of hatching successfully, unlike their more distant cousins such as the long-necked sauropods and living crocodilians.

[Related: Whoa, dinosaur eggs looked more dope than we thought]

“Tucking behaviour was usually considered unique to birds, but our new findings suggest that this behaviour could have existed and first evolved among theropod dinosaurs—the ancestors of modern birds,” Ma said.

To confirm this possibility, however, researchers will have to unearth more fossilized embryos of theropods and other kinds of dinosaurs to compare with modern birds and crocodiles. Ma and her colleagues also plan to investigate the skull and other body parts of this embryo still hidden within the rock.

“We hope to answer more questions about dinosaur early development and growth with this exceptional specimen,” she said.

Does South Africa still need private rhino breeders to fight poaching?

Ed Stoddard is a Johannesburg-based journalist with a focus on resource industries, wildlife, economics, and the environment in Africa. A Reuters correspondent for 24 years, he is now a regular contributor to the South African news site The Daily Maverick.

This story originally featured on Undark.

Three hours outside Johannesburg, the gravel road to John Hume’s home slices through grasslands tinged a parched amber hue as the winter dry season fades. The former hotel mogul owns the world’s largest privately held rhino population: 2,000 southern white rhinoceroses, roaming 21,000 acres of former crop and cattle lands. A 60-mile long electrified fence rings the property. Its two-fold role is to keep the pachyderms in and poachers out.

Hume has not lost a rhino to poachers in almost five years, thanks to formidable security. Over the past decade though, state-run parks have been overwhelmed by poachers, who can sell a single rhino horn for six-figure sums. As those wild populations decline, research suggests nearly half of South Africa’s estimated 12,300 white rhinos are now in private hands. With the trend of private breeding growing rapidly, some experts say this number may even have already surpassed 50 percent.

But the fate of Hume’s rhinos—and South Africa’s unusual game privatization experiment—hang in the balance. In December 2020, a government panel recommended phasing out intensive and captive rhino breeding in the country, as part of a broader set of policies for wildlife conservation. According to the panel and a subsequent government policy paper, captive breeding operations like the one owned by Hume are potentially harming the species’ future.

In an email to Undark, the panel’s chair, Pamela Yako, expressed two concerns about intensive breeding and management: “that this, firstly, compromises the genetics of the population and secondly compromises their ability to independently survive in the wild.”

While Yako and her colleagues acknowledge the role of private reserves in helping to build up rhino populations, they conclude it’s time to move the more intensively managed private populations back into wilder habitats.

The panel’s report has been accepted by the South African cabinet, signaling top-level political support. After a public comment period, the Department of Forestry, Fisheries, and the Environment will refine the policy, then draft a white paper to send to Parliament.

But the prospect of losing their herds has alarmed many private rhino owners and conservationists, who say the policy will make southern white rhinos more vulnerable to poaching. “We have rhino in well-protected zones,” says Pelham Jones, chairman of the Private Rhino Owners Association, or PROA. Now, he adds, “the government is recommending that these captive breeding operations, which have proven to be highly, highly successful, and are achieving the best breeding outcome one could hope for, are to be shut down.” The group is considering all options, including a legal challenge that would potentially ensnare the process in years of legal wrangling.

At stake here are questions about how best to preserve a threatened species. The politics are fraught as well, and charged by South Africa’s racial tensions: Proponents of the new policy point out that the country’s Black majority has often been excluded from the benefits of rebounding game populations. By PROA’s own estimates, there are between 150 and 180 private rhino owners in South Africa; nearly all of them are White.

None of them has an operation as large as Hume’s, whose herd may account for up to 13 percent of the global population of white rhinos. His ranch also appears to be a prime target of the new legislation. In her email, Yako expressed concerns about “a single operation that has a large number of rhino under intensive management and breeding”—seemingly a reference to Hume, although Eleanor Momberg, a spokesperson for the Department of Forestry, Fisheries and the Environment, wrote in an email to Undark that Yako and other panelists were no longer available for further comment because their contracts had expired.

The new policy could eventually undermine the legal basis for Hume’s breeding project, leaving the herd in limbo. It’s unclear who would take over Hume’s herd—and how a South African state balancing intense fiscal pressures with massive social needs would pay for a mass rhino relocation.

Sitting in his modest home office, which is adorned with rhino pictures and carvings, Hume maintains he is adding to an endangered species’ numbers. “Surely that’s what we all want,” he tells Undark. “Show me the good grazing, and assure me that you can keep the bullets away, and I will show you my rhinos thriving.”


Africa is home to two of the five surviving rhinoceros species: the larger white rhino, a grass grazer, and the smaller black rhino, which browses on trees and bushes. In the late 19th century, European settlers killed thousands of the animals. Every southern white rhino today is descended from a single population in South Africa’s KwaZulu-Natal province. In the 1890s, the animals reached their low point, numbering just a few dozen.

From this bastion—now called the Hluhluwe-Imfolozi Park—the population rebounded. By the 1960s, flush with rhinos, a government organization called the Natal Parks Board began selling and donating animals to other African reserves, and to zoos around the world. In 1986, Natal Parks Board started selling to private operations, too. Five years later, the South African government passed the Game Theft Act, which allows people to own rhinos and other game on their property, provided it has been enclosed with fencing.

The law has critics. In a 2015 dissertation, scholar Dhoya Snijders described the act as “one of the largest and most unnoticed transfers of common goods to private landowners in the country’s history.”

Thanks to the new legislation, game ranchers began to rapidly accumulate rhinos to breed and trade for profit, to draw ecotourists, and to stage expensive hunts. Nowadays, most owners also slice off the animals’ horns and store them, in the event that a now 44-year-old global moratorium on the rhino horn trade is lifted. These owners argue that trading rhino horn may help regulate its illicit traffic and would provide substantial revenue to cover the large costs associated with managing and conservation of the species, said Jones. Comprised of keratin—the substance in human fingernails—rhino horn can grow back after it is trimmed, an operation that entails tranquilizing the animal. De-horning is also aimed at thwarting poachers by removing their ultimate target.

By 2010, there were 18,800 white rhinos in South Africa, according to estimates from the International Union for Conservation of Nature, of which at least 5,500 were privately owned.

But as demand for rhino horn grew in newly affluent Asian economies such as Vietnam—where consumers prize its alleged medicinal properties—poaching surged. A record 1,215 rhinos were poached in South Africa in 2014.

Although numbers have dropped since then, poachers still take hundreds of animals per year. The activity has centered on Kruger National Park, South Africa’s flagship wildlife reserve. The park is vast—roughly the size of New Jersey—making it difficult for the cash-strapped government to police. And entrenched poverty in neighboring communities has pushed some people toward poaching.

Today, as state losses mount, poachers are increasingly targeting private reserves. Government data shows 15 percent of rhinos poached in 2019 were on private land. In the first six months of 2021, that spiked to 30 percent. Owners who can afford it invest heavily in security. Meanwhile, many small-scale rhino ranchers have sold out because of costs.

At least so far, the scale of Hume’s operation—and his deep pockets—have fended off poachers. At Hume’s “Ops Center,” 10 TV screens line one wall. Radars and thermal cameras monitor the property, covering the rhinos’ range and the public roads that cut past the ranch. The flat, grassy terrain is ideal for the motion-detecting radars, which cannot penetrate solid objects such trees or buildings. If an intruder gets over the electrified fence, concealed speakers blare warnings while a team rushes to intercept.

“We are always ready, and we can fly a chopper to the scene quickly if we need to,” says Brandon Jones, a helicopter pilot and Hume’s head of security, with a handgun holstered to his hip. The team’s arsenal includes assault rifles; the poachers are also heavily armed. Hume, who refers to the team as his “private army,” said security costs him $2 million per year.

Although numbers have dropped since 2015, poachers still take hundreds of animals per year. The activity has centered on Kruger National Park, South Africa’s flagship wildlife reserve.

The investment seems to be working. While poachers killed 32 of Hume’s rhinos between 2007 and 2017, he says he has not lost an animal since. More of his rhinos have been killed by lighting strikes.

According to Hume, the operation has accumulated nearly 9 tons of rhino horn, worth a nine-figure sum on the black market. But, he said, his passion for rhinos was driven by the species’ plight in the cross-hairs of poachers, not potential profits. “I always liked breeding,” he says. “I became aware in the early ‘90s of the slaughter of rhino elsewhere in Africa. They were being slaughtered to extinction.” Around that time, he purchased his first 10 animals.

Today, driving around the property, it’s possible to see clumps of rhinos amid the windswept landscape of long wild grass, punctuated by the occasional tree. Other times, there are no signs of the big critters at all, beyond their telltale scat in the soil.


Inside this gated fortress, the number of rhinos on Hume’s ranch has swelled: Between 2008, when he started breeding at his current ranch, and September 2021, Hume’s rhinos had given birth to some 1,690 calves. But whether that growth is an unmitigated good for rhino conservation, or a liability for the future of the species, remains contested.

Yako and other critics of captive breeding have raised concerns that the closely managed life on the ranch could give rise to domestication, a fate that historically has not occurred in any large African mammal, or render the rhino unsuitable for rewilding.

Hume’s rhinos are divided into breeding areas surrounded by electric fencing averaging 1,200 acres. The animals roam, graze, and mate freely in their allotted spaces. But they are intensely monitored, and each enclosure or camp has a ranger who does a daily headcount, often on horseback. Still, Michelle Otto, Hume’s resident and full-time veterinarian, said the animals are far from domesticated. “We are only on our second generation now,” she said, as she prepared medicine for an old cow rhino with hip problems. “I’ve been chased into a tree by a white rhino here because I went in on foot, and one didn’t take a liking to me, and she stormed me.”

Otto said the animals can be habituated to certain vehicles—but, she noted, even wild Kruger rhinos are now accustomed to cars. The ranch does supplemental feeding, mostly in the dry winter months, which Otto said was at most 40 percent of the rhinos’ daily intake. “The rest they take off the veld,” she said.

Some of Hume’s rhinos have already been successfully reintroduced into the wild. Hume sold his last 16 black rhinos—famed for their ornery temperament—to the small kingdom of Eswatini, which borders South Africa. “This group of rhinos has been suitable for introduction, save for one young male which was hand-raised,” wrote Mick Reilly, conservation and security executive with Eswatini’s parks, in an email.

“Hume’s white rhinos as a whole would be suitable for re-introduction into the wild,” added Reilly, who has visited the ranch.

Tranquilized white rhino bull getting dehorned in South Africa
A tranquilized bull rhino gets a trimming at John Hume’s ranch in South Africa on August 5, 2021. Most owners slice off the animals’ horns, which will regrow, and store them in case the moratorium on the rhino horn trade is lifted. De-horning also thwarts poachers by removing their ultimate target. Ed Stoddard/Undark

Yako and others have also expressed concerns about the genetic diversity of rhinos in captive breeding populations. Even in the wild, rhino genetics pose serious issues: A century ago, when population numbers were so low, the bottleneck reduced the genetic variability of the species. According to Petra Kretzschmar, a biologist and rhino expert at the Leibniz Institute for Zoo and Wildlife Research in Germany, this state of affairs made the species vulnerable to disease and fertility problems.

Compounding the issue, rhinos tend to mate with their relatives. “Inbreeding is unfortunately a big threat to the white rhino population,” Kretzschmar wrote in an email. “It is therefore very important to prevent rhinos from inbreeding.”

In a 2020 study of rhino breeding patterns on a large private ranch in South Africa’s northern Limpopo province, Kretzschmar and several colleagues found that white rhinos are not choosy about mating with kin. The study, published in the journal Evolutionary Applications, found “no sign of inbreeding avoidance: Females tended to mate more frequently with closely related males.”

The researchers recommended rotating breeding bulls every six years—the time it takes a female to reach sexual maturity—between reserves.

Kretzschmar, who has visited Hume’s ranch, says policies there do effectively address the issue. Otto keeps detailed records in a stud book to prevent inbreeding. Compared to the private reserve where her study was conducted, Kretzschmar says in a phone interview, Otto “has the benefit that the rhinos can be monitored much better,” as they are put into a smaller spaces that can be more readily observed.

“So her records are much more accurate, which results in the fact that she knows exactly who has fathered whom and can immediately move an animal to a different camp to prevent inbreeding,” says Kretzschmar.

In the paper, Kretzschmar—who also does paid consulting for a private game ranch—and her co-authors said South Africa’s private reserves may be the last refuge for the species.

Still, Hume’s approach has critics.

“In John Hume’s case, there is control over the breeding,” says Dave Balfour, an ecologist and member of the IUCN African Rhino Specialist Group who contributed to the government report arguing for reimagining rhino conservation in the region. He says these breeding strategies “are not anywhere near the gold standard.”

“A natural rhino population has 50/50 male/female” Balfour says, adding that Hume’s project had somewhere between 50 cows to three or four bulls. “That is not a natural mating selection system.” (In a WhatsApp message, Otto defended the ranch’s arrangement. “We are a breeding operation, therefore we are skewed towards having higher female densities in a set location than in the wild,” she wrote, adding that females are permitted to choose among two or three bulls.)

Other critics have concerns about the stockpiling of rhino horn, detecting a profit motive beneath a facade of conservation. “Are you trying to mask an economic incentive behind a conservation philosophy?” asks Neil Greenwood, the Southern African director for the International Fund for Animal Welfare, an NGO. “I don’t think that the captive breeding is necessarily the most effective way to protect those animals.”


At issue are larger questions about the future of wildlife in South Africa, where populations of large, charismatic animals have rebounded. Many are in private hands: Today, according to the government report, there are 9,000 private game ranches in South Africa, comprising around 50 million acres.

The growth of private game reserves has raised some concerns about equity. South Africa is the most unequal society in the world, according to the World Bank, and land ownership patterns remain skewed in favor of the White minority.

According to the government policy paper, many communities with historical ties to wildlife lands have been walled out of the present conservation arrangement. “The forceful removal of people from the land led to the current South African ‘Wildlife Model,’ the report says, “where the largest percentage of wildlife land is owned by the White minority and by the state, with few wildlife resources on community lands.”

Critics note that these conservation disputes are unfolding amid persistent government failures to enact land reforms. “The disparities in ownership in the wildlife industry somewhat reflects what we see in other sub-sectors of agriculture, where participation of Black farmers remains marginal,” says Wandile Sihlobo, the chief economist at the Agricultural Business Chamber of South Africa and author of a recent book on land reform in the country.

As part of its vision, the government panel calls for the removal of fences separating many conservation areas. The report envisions “an authentic wild sense of place” with “larger contiguous areas containing vibrant self-sustaining populations” of elephants, buffalos, lions, leopards, rhinos, and other species.

“Are you trying to mask an economic incentive behind a conservation philosophy?” 

Neil Greenwood, International Fund for Animal Welfare

That’s far from the present reality: In South Africa all megafauna except leopards are contained in fenced areas of some kind. And the government panel’s broader vision of wildness has elicited some skepticism from conservationists—and private rhino owners. In a written submission raising objections to the new policy, PROA argues that “human beings in South Africa and across the world simply do not have the luxury of a utopian concept of wild animals roaming across millions of hectares of unfenced, uninhabited, and human-free plains.”

In an email, Momberg wrote that Barbara Creecy, minister of Forestry, Fisheries, and the Environment, preferred not to comment, explaining that officials are still reviewing public responses to the proposal.

For now, Hume’s rhino breeding operation is continuing to grow. On a recent morning, Otto and other Hume employees prepared to dehorn 19 bulls—a brisk, clinical undertaking.

While the rhinos may live carefully managed lives on a ranch, they remain dangerous. Aiming a rifle-like tranquillizer gun out the window of her Toyota Landcruiser, Otto shot a dart into each rhino, generally from around 50 yards. As the rhino wobbled, a member of the up to 15-person crew pulled a blindfold over its eyes, while several men ran in to keep the animal upright. Once the rhino was lying on its chest, one of the ranch’s managers used a hand-held electric saw to do the trimming.

“We are cutting above the growth plate,” Otto said as the saw sliced through the horn of a 2-ton bull. “The section they are trimming is excess horn that contains no blood vessels or nerves.”

When the trimming was complete, Otto injected the rhino with an antidote to the tranquilizer.

“You don’t want to be next to him when he wakes up,” she cautioned. The situation was unnatural, but a rhino is a rhino.