Capybaras In Posh Neighborhood Get Vasectomies

A gated community in Argentina – built on a wetland along the Luján River, north of Buenos Aires – is home to about 45,000 wealthy residents and at least 1000 capybaras. The humans who live in Nordelta are about to deploy assorted birth control methods on the growing rodent population.

The capybaras were here first, of course, as Nordelta was developed only in the last twenty years. Although the landscaped homes have dramatically altered the habitat, the capybaras like it here, so much so that their numbers have tripled in just over three years. 

As the largest rodent in the world, an adult capybara can weigh 125 pounds or more and measure over four feet long. These vegetarian, amphibious giants live in colonies led by an alpha male, a harem of females, and their young. Lots of young.

“From the window I see eight capybaras, four adults, and four young. Some are in the water. The family has about 15 members,” Marcelo Cantón, spokesman for the Nordelta Neighborhood Association, tells El Pais. Cantón says capybaras were scarce here until 2020, then their numbers surged.

“This is an almost perfect environment for them. They have plenty of space for shelter and food and nobody hunts them.” Because Nordelta has no natural predators (such as pumas) or unnatural ones (such as poachers), the capybaras reproduce faster. The residents don’t want to kill or even move the animals – where would they go? – so they’re turning to birth control.

Not going to be easy. One team of researchers launched a pilot program to capture dominant males and give them vasectomies. They’ve so far snatched and snipped five of these harem heads; now they’re waiting to see whether this truly reduces fertility. Another plan involves injecting two doses of contraceptives into 250 animals, which would slow down reproduction for up to a year, after which they’d have to do it all over again.  

Some environmentalists are pushing for less intervention and more legislation, namely for laws that protect the wetlands and prevent further development on them. Capybaras are not an endangered species, though they might end up that way if humans continue to encroach on their habitats. 

Photo credit: Nordelta