Aoshima (青島, Aoshima), also known as Cat Island (猫の島, Neko no shima), is an island in Ehime Prefecture, Japan, known for its large number of feline residents. Felines have been reported by news outlets to outnumber humans by ratios between 6:1 and 10:1, but in recent years as elderly inhabitants of the island have died, it has skyrocketed to nearly 36:1.[note 1] They were introduced to combat rodents on fishing boats, but remained on the island and reproduced in large numbers.
The island is roughly 1 mile (1.6 km) long. It was formerly part of Nagahama in Kita District, but as of 2005, is part of Ōzu.