Aoshima, also known as Cat Island, is an island in Ehime Prefecture, Japan, known for its large number of feline residents and small number of human residents. Felines have been reported by news outlets to outnumber humans by ratios between 6:1 and 10:1, but as elderly inhabitants of the island have died, the ratio has greatly increased to …Aoshima, also known as Cat Island, is an island in Ehime Prefecture, Japan, known for its large number of feline residents and small number of human residents. Felines have been reported by news outlets to outnumber humans by ratios between 6:1 and 10:1, but as elderly inhabitants of the island have died, the ratio has greatly increased to almost 36:1. Felines were introduced to combat rodents on fishing boats, but remained on the island and reproduced in large numbers.