The Japanese word for rhinoceros is sai. See more rhinoceros words translated into Japanese in the table below.
Interesting facts about rhinoceroses in Japan
All rhinos, especially the white rhino, are endangered species. The Leofoo Safari Park in Taiwan shipped in 8 white rhinos from Africa in 1979 to breed them in the hopes of increasing their numbers. The program worked as they now have 22 white rhinos, which makes it one of the most successful breeding projects in the world.
Japan has 2 male white rhinos and has recently shipped a female from the Leofoo Safari Park in the hopes of further increasing their numbers. Read more about it here.