Unregulated tourist feeding has pushed Japan’s famous “Rabbit Island” beyond its natural ecological limits, decimating local plant life and causing wild boars to prey on surviving rabbits.On Okunoshima, an island in Hiroshima Prefecture, heavy feeding by visitors has caused rabbit numbers to exceed what the local environment can naturally support. According to a study published in the Journal of Ecotourism on July 29, 2026, this constant stream of food is reshaping the behavior of local animals and causing widespread environmental damage.The study was written by Professor Shingo Kaneko of the Faculty of Symbiotic Systems Science and Engineering at Fukushima University, in collaboration with researchers from co-author Asami Ogura, Associate Professor at the National Institute of Technology (KOSEN), Kure College, Kobe College, and University of Tokyo, Japan. The project began when the creators of the children’s picture book Usagi no Shima (Rabbit Island) asked the team to investigate the origins of the animals and investigate local wildlife health.
Wild boars become adapted to hunting live prey
The extra food brought by tourists has changed the way different animal species interact on the small island. Researchers observed wild boars eating rabbit food scraps, scavenging dead rabbits, and attempting to catch live rabbits.“When we first heard that a wild boar had hunted a live rabbit, we were amazed,” Kaneko said. “Wild pigs are known to scavenge animal carcasses, but they are not generally thought of as animals that actively hunt live prey.”Fieldwork revealed that wild boars, rabbits and humans were constantly crossing paths.“At the same time, during our fieldwork, we were amazed at how closely wild boars, rabbits and humans were interacting on the island. “In this isolated environment, events different from what we typically see elsewhere seem to be occurring throughout the island,” Kaneko explained.Researchers suggest that several things are happening at once. Leftover food draws pigs directly to areas full of rabbits. Having so many rabbits in one place leads to more dead rabbits and more frequent head-on encounters between the two species, leading to unusual hunting habits.
plants dropped to the ground
Okunoshima rabbits are not native Japanese rabbits. They are European domestic rabbits that were introduced to the island, established a population and increased their numbers.Their numbers depend heavily on human handouts. Before the COVID-19 pandemic, rabbit numbers increased due to heavy tourism, but declined rapidly as travel decreased during the lockdown.This artificially overpopulated area has harmed the island’s plants. Overeating has created a clear “rabbit line” across the landscape, where low-growing bushes and low tree branches have been completely eaten away.
Okunoshima, also known as “Rabbit Island” in Japan, attracts tourists from all over the world who want to establish genuine friendships with the local rabbits that roam the island.
Food scraps attract scavengers
The ecological damage goes beyond rabbits and pigs. Scavenger birds such as crows and black kites have also gathered around feeding sites to eat leftover remains and animal remains, altering the wider local ecosystem.The researchers pointed out that their findings do not mean that wildlife tourism should be banned. Instead, they argue that food needs clear regulations and active monitoring to prevent further damage.The author recommends establishing a long-term plan for Okunoshima. Key steps include controlling feeding practices and food sales, tracking rabbit numbers, helping plants recover, and studying how other animals are affected.The researchers suggest that local communities, tourism businesses, scientists, and government agencies should work together to protect both the local wildlife and the island’s environment.
History and legacy of poisonous gas
Long before it became famous for its friendly rabbits, Okunoshima had a darker name: “Poison Gas Island.” During World War II, the Japanese Imperial Army erased the island from official maps to build a secret factory that produced more than six thousand tons of mustard gas and tear gas.After the war, Allied forces destroyed the chemical plants and buried or dumped the remaining chemical weapons. The island was later converted into a national park, and the Okunoshima Poison Gas Museum opened in 1988 to educate visitors about the wartime history of the site.
Hidden consequences of irregular feeding of rabbits on Okunoshima Island
How did domestic rabbits take over?
The origin of the current rabbit population remains a matter of local debate. A popular belief suggests that eight rabbits were released by local schoolchildren in 1971. Another theory holds that the current animals are descendants of test rabbits used in wartime poison gas laboratories, although genetic studies indicate that they are domesticated European rabbits that were introduced much later.Because the entire island is designated as a protected park area, predators such as dogs and cats are strictly prohibited. Without the dangers of natural predators or traffic, the introduced rabbits grew rapidly, growing from a small group to a population that numbered more than a thousand animals at its peak before declining in recent times.