A family of capybaras near a lake in Nordelta, a gated community north of Buenos Aires. Photo / Anita Pouchard Serra, The New York Times
The world’s largest rodent is multiplying in - and dividing - one of Argentina’s most exclusive gated communities.
Luciano Sampietro lifted a 3-foot aluminium pipe to his lips and blew, sending a blow dart laced with sedatives, muscle relaxers and painkillers toward the world’s largest rodent, lounging near an artificial pond.
The veterinarian’s target, a roughly 50kg alpha male capybara, was hit in the hind leg. Sampietro fired again and struck a female. Within 15 minutes, workers dressed in the tan outfits of safari guides scooped up the sleeping patients.
But they were too late: the female was already pregnant. So they injected the male with a drug designed to stop him from impregnating any more.
Yes, in the wealthy suburbs of Buenos Aires, they are sterilising the capybaras.
The rotund, laid-back, dog-sized rodents native to South America have recently become a darling of the modern internet. They have catapulted to the top of the unofficial adorable animal rankings via countless videos showing them mellow, plump and perfectly happy to let monkeys and ducks ride on their backs. Their image adorns backpacks and stuffed animals, and in Tokyo, tourists pay premiums to feed them carrots at capybara cafes.
But to some people in one corner of their native land, the cuddly capybara has become a menace.
Since the pandemic, “carpinchos,” as they are known in Argentina, have proliferated in Nordelta, a ritzy, picturesque gated community of 45,000 people north of Buenos Aires. When residents retreated indoors in 2020, the capybaras began to colonise the manicured neighbourhoods, finding green grass, fresh water and no predators, according to biologists hired by the community.
Over the past two years, the biologists estimate Nordelta’s capybara population has tripled to nearly 1000, posing a tricky test case for the urban co-existence of humans and wildlife.
On a visit last month, capybara families grazed near the tennis courts, dozed on the volleyball courts and waded in the artificial lagoons. Just past a sign warning of crossing capybaras, a family crossed the street in a single-file line, illuminated by waiting headlights.
Sure, most residents admitted, the capybaras are cute. But they also cause traffic accidents, chomp their way through gardens and, on occasion, have attacked some of the community’s smallest dogs.
“It’s a wild animal versus a domesticated dog. I mean, it’s totally different,” said Sampietro, the veterinarian hired to help manage the capybara population. “I’ve had to do necropsies on capybaras and it’s difficult to cut the hide with a knife.”
Pablo Pefaure, one of Nordelta’s 26 neighbourhood representatives, said his neighbours frequently complain to him about the amphibious rodents. “They see them as dangerous, they see them as invasive, they fear for their young children,” he said.
He said that capybaras have sometimes followed his miniature schnauzer, Grumete. “I don’t leave him alone in the garden because I don’t know what might happen,” he said.
His neighbour sitting nearby, Veronica Esposito, did not agree. “No capybara has ever approached my dogs,” she said. “Everyone says they eat the plants. Yes, they do. But the plants grow back,” she added. “I don’t see the problem.”
Esposito is one of a small group of neighbours leading a rebellion against the capybara controls. They have protested in the streets, taken legal action against developers and gathered 25,000 signatures for an online petition to protect the animals. They’ve also attracted 34,000 followers to an Instagram page where they sometimes shame their neighbours, including one who had used a whip to scare capybaras off her dock.
“I believe their adorableness is a strategy of the species itself to survive,” said Silvia Soto, the most vocal neighbour. “Their lovability has conquered us, and we’re fighting for them.”
So far, the fight has not worked. Last year, Argentina’s national Government began an experiment to perform vasectomies on three capybaras in Nordelta, hoping to track how it affected the males’ standing in their packs. If successful, the practice could be expanded.
In February, the Nordelta organisation told residents in an email that it was moving ahead with a different plan: a “contraceptive vaccination programme,” approved by the local Government, to sterilise 250 adult capybaras.
Costanza Falguera, the organisation’s lead biologist, said her team is using a “vaccine” that halts the production of sperm and inhibits ovulation. It requires two injections several months apart, but then might last only for several months, meaning they might have to keep tranquillising the capybaras repeatedly.
They aren’t sure how long the sterilisation lasts because the drug – Improvac, made by a New Jersey drugmaker, Zoetis – has not been used on capybaras. It is designed to alter pigs’ hormones before slaughter so the meat tastes better. “Only for use in male pigs,” Zoetis says on its disclaimer for the drug.
In 2019, Nordelta sprayed its grass with the scent of a carnivore, scaring off many capybaras. But Falguera said the efficacy dropped over time as the capybaras in Nordelta became long removed from having regular predators.
So, she said, the community settled on the injections, which she said are better than castration or vasectomies because they are less likely to alter the rodents’ behaviour and group dynamics.
In other words, they still mate, she said, “but they don’t fertilise”.
The decision to sterilise the capybaras ultimately rested with one of Argentina’s richest men, Eduardo Constantini, an entrepreneur and real estate developer whose company controls the Nordelta organisation. His spokesperson did not respond to requests for comment.
To the capybara advocates, intervening in the animals’ reproduction is an escalation of Nordelta’s attack on the species.
Thirty years ago, Nordelta was largely untouched wetlands where capybaras roamed freely, hunted by pumas, jaguars, caiman and sport hunters. In the late 1990s, Constantini began transforming the area with roads, ponds, mansions, condo towers, a shopping centre and a golf course designed by American golfer Jack Nicklaus. Construction has been nearly nonstop – with 17 more buildings underway now – and it is now home to some of Argentina’s richest people.
Soto argued that the capybara population is only increasing because developers destroyed the animals’ wild habitat, forcing them out of the forest and into the suburbs.
“In a matter of hours they knock down a forest,” Soto said. “What happened to the wildlife? Have they died? Have they been displaced?”
Her group is pushing for the capybara to be given their own nature reserve, but there appears to be little interest from Nordelta’s developers. “I don’t understand how they can only think of vasectomy and sterilisation,” she said.
On a recent weekday, as capybara grazed on a playground, Lidia Schmidt and Felipo Contigiani walked past, hardly noticing. The married couple agreed the capybara population had to be checked somehow, but they did not see eye to eye on the causes of the problem.
Contigiani, who said that he used to hunt capybaras as a child, had less sympathy for the animals. “It’s a wild animal that came to live in the city,” he said.
His wife corrected him. “No, the city came to settle where the wild animal was,” she said. “It’s the other way around.”
This article originally appeared in The New York Times.
Written by: Jack Nicas
Photographs by: Anita Pouchard Serra
©2025 THE NEW YORK TIMES
The conflict has entered its seventh day.