In life, countries often have to make hard, even desperate, choices. Take South Africa, which is trying to eradicate the mice that eat live seabirds by bombarding them with poison. Another project injected radioactive material into the horns of rhinos to make them easier to spot and reduce poaching. And in Australia, officials have hunted wild cats to prevent them from wiping out local wildlife. Meanwhile, the U.S. has set out to eliminate thousands of barred owls to save spotted owls from extinction.
But sometimes things don’t work out as governments plan. Just ask Japan.
The 1979 incident. The story begins in 1979 on the Japanese island of Amami Ōshima in Kagoshima Prefecture. That year, explorers rediscovered the Amami rabbit (Pentalagus furnessi), an endemic species considered a “living fossil” due to its evolutionary antiquity. Before the finding, experts believed the rabbit was on the verge of extinction due to habitat loss and hunting.
The discovery marked a turning point for the conservation of the species. It highlighted the importance of protecting the island’s natural environment, home to many other unique species. The event also underscored the need for better conservation efforts on Amami Ōshima, which lead to the attempt to eradicate or control the snake population.
The wrong “bomb.” As such, within a few months, Japan set a plan in motion. It introduced about 30 mongooses to the island to wipe out the snakes, specifically the habus (Protobothrops flavoviridis), which threatened the local population. On paper, the idea appeared to be a seamless plan: The mongooses, natural snake predators, would reduce the number of habus and improve safety on the island at all levels.
However, this project was far from infallible. This small terrestrial carnivorous mammal wasn’t the ideal creature to eradicate snakes. First, they’re active animals during the day, while habu are nocturnal snakes. As a result, these reptiles continued to inhabit the island for decades, which had an enormous ecological impact.
A habu snake (Protobothrops flavoviridis).
Predation on endemic species. Thus, during the day, instead of focusing on habu snakes, mongooses began to prey on a wide range of native species, including several that had no natural predators on the island. This severely impacted the local fauna, especially endemic and endangered species, such as the newly rediscovered Amami rabbit.
Hundreds of thousands of mongooses. At some point, the carnivorous mammal introduced by the government to eradicate a pest became an even more significant and dangerous one. Around the year 2000, the mongoose population peaked at nearly 10,000 specimens. In fact, Japan had already launched a species control project in 1993, which the authorities expanded over time.
How? Experts set about 30,000 traps on the island to catch the animals. They also installed cameras with sensors to monitor them. Residents formed the Amami Mongoose Busters team, which specialized in catching mongooses (they caught thousands).
The end? The last official capture of a mongoose on the island was in April 2018. Since there have been no captures of the species for a long time, a panel of experts estimated the eradication rate was between 98.8% and 99.8% in February this year. As such, they concluded that it’s reasonable to say that the government has eliminated mongooses from the island.
Finally, on Sep. 3, the Japanese Ministry of Environment declared the eradication of non-native mongooses on Amami Oshima Island, a UNESCO World Heritage Site. The ministry based its declaration on the opinion of the expert panel, citing the fact that no mongoose trapping has been confirmed for more than six years since the last capture in April 2018.
A unique case. The Ministry of Environment has made no secret of the disaster of the 1979 attempt to control the snakes. In fact, it’s one of the most significant cases in the world where the government has eradicated non-native mongooses that had invaded an area during such a long period of time.
The ministry said it will remove the traps placed on the island. However, it will continue to monitor the area with cameras to prevent a new group of these little creatures from invading. Given that it took half a century to get them off of the island, any contingency method is more than understandable.
Images | Animalia, TANAKA Juuyoh, Patrick Randall
Related | Tiny Creature Discovered on the Alaskan Border Is the Closest Living Relative of All Animals
View 0 comments