Photo/IllutrationThe Amami rabbit is listed in the “Endangered Class IB” category. (Asahi Shimbun file photo)

Endangered Amami rabbits, found only on two islands in Kagoshima Prefecture, have made a resounding comeback since the eradication of predatory mongooses started more than a decade ago, according to the Environment Ministry.

Only 2,000 to 4,800 Amami rabbits were believed to have inhabited Amami-Oshima island in fiscal 2003, while the figure for Tokunoshima island was estimated at 200.

The population is believed to have topped 15,000 on Amami-Oshima island in fiscal 2015.

Measuring 40 to 50 centimeters long, the rabbits are said to maintain primitive characteristics.

Mongooses were brought to the island to control the population of venomous “habu” snakes and rats. But the aggressive mammals started attacking the rabbits, leading to a plunge in their numbers.

The central government in fiscal 2004 began a project to protect and breed Amami rabbits while eradicating the mongooses.

The Asahi Shimbun asked the Environment Ministry to disclose relevant data for fiscal 2015 and found that the rabbit population on Amami-Oshima was estimated at 15,221 to 19,202. The estimate, the first since fiscal 2003, was based on the amount of their excrement and other information collected along 24 routes.

For fiscal 2015, the ministry introduced a new method to gain more accurate estimates. It combined image data captured by cameras set up in forests over a nine-year period with the excrement study findings.

Based on the method, the rabbit number is estimated at between 16,580 and 39,780.

Some experts say the ministry may have overestimated the rabbit population, given the wide range in the estimates.

But Yuki Iwasa, head of the wild animal section of the ministry’s Naha Nature Conservation Office, said both estimates were conducted properly.

“The number of Amami rabbits is no doubt on the rise,” Iwasa said. “Both approaches show there are at least 10,000 to 20,000 rabbits, and the estimates are consistent with observations by local staff.”

He added that more detailed analysis is necessary.

Amami rabbits are currently listed in the “Endangered Class IB” category, meaning the species has “a high risk of extinction in the wild in the near future.”

The ministry is considering designating the rabbits in the less-at-risk “Endangered Class II” or even lower categories by fiscal 2023.

Japan is seeking inclusion of areas around Amami-Oshima on UNESCO’s World Natural Heritage list. The rise in the Amami rabbit population could improve the chances for the listing.