HYOGO, Nov 04, 2025 (News On Japan) - Farmers across western Japan are facing mounting losses from the growing population of nutria, large semi-aquatic rodents originally brought from South America. Once imported for their fur, the animals have become a major agricultural pest, chewing through crops and spreading rapidly into urban areas.
In Hyogo Prefecture’s Kasai City, one farmer reported that nearly 90 kilograms of rice—just days from harvest in August—were eaten by nutria. “It’s exhausting,” he said. “After working so hard to grow it, they took everything right before I could harvest.” Last year, he lost around 200,000 yen worth of vegetables under similar circumstances. Damage from nutria nationwide is estimated to reach 50 million yen annually.
Nutria were introduced to Japan decades ago for military uniforms and later escaped into the wild, thriving in the mild climate of western Japan, where they have few natural predators. The rodents, which resemble small capybaras, are excellent swimmers and can dig burrows up to six meters long—sometimes undermining stone walls. At Himeji Castle, a UNESCO World Heritage site, nutria have been captured in the moat area to prevent damage to the stone embankments.
The species’ breeding rate makes containment difficult. According to experts, a single female can give birth up to three times a year, producing as many as seven or eight offspring each time. “Depending on conditions, their numbers can increase extremely rapidly,” one specialist warned.
Some municipalities are now offering bounties to encourage local trapping. In Kato City, Hyogo Prefecture, authorities pay 3,000 yen per captured nutria. One man has already caught 26 animals under the program. “I thought, if catching them can help protect farmers, I’ll give it a try,” he said.
Nutria have also been sighted in central Osaka, swimming in rivers near JR Sakuranomiya Station. Despite their calm appearance, experts caution that they can transmit infectious diseases through urine and inflict serious bites capable of fracturing bones.
Efforts are also emerging to turn the problem into an opportunity. In Shizuoka Prefecture’s Iwata City, local hunters, farmers, and university researchers have teamed up to process nutria meat as food. A restaurant in Osaka even serves nutria confit, described by diners as having “a mild flavor and texture similar to chicken.” The chef says the ingredient “defies its negative image and has surprising culinary potential.”
While some hope culinary use might help manage the population, authorities warn that nutria are designated as a “specified invasive species.” Any handling or sale of the animals requires special permits from local governments. For now, Japan continues to grapple with how to curb this resilient intruder—before it takes an even greater bite out of the nation’s farms and heritage sites alike.
Source: KTV NEWS
