Kagoshima: Zoo Succeeds in Breeding Rare Spiny Rats, Endangered Spieces

The Yomiuri Shimbun

12:22 JST, August 2, 2025

KAGOSHIMA — Hirakawa Zoo in Kagoshima has successfully bred Amami togenezumi, or Amami spiny rats, an endangered species. The rare rats are kept at eight facilities in Japan, and the zoo became the seventh facility to successfully breed them.

The spiny rats are rodents that grow to lengths of 10 to 15 centimeters. Their fur includes characteristically needle-like hairs. They inhabit only Amami-Oshima Island in Kagoshima Prefecture and are nocturnal, feeding on acorns and insects. Unlike most mammals, their males lack the Y chromosome that ordinarily determines male sex.

According to the zoo, five babies — three males and two females — were born. In mid-May, one female rat stopped coming out of her nest, prompting the zoo staff to observe her with a monitor. They discovered that the rat had given birth on April 26 and confirmed all five offspring on May 19. The mother rat and her offspring are all said to be healthy.

The Environment Ministry believes that the number of Amami spiny rats decreased due to predation by mongooses and wildcats as well as the deterioration of their habitat caused by road construction that has divided forests. In 2017, the ministry partnered with universities and others to begin conservation activities. They transferred the spiny rats they captured to domestic zoos, including Hirakawa Zoo, which has been working to keep and breed the rats without exhibiting them.