Aoshima is a small island in the Seto Inland Sea, which separates three of Japan’s four main islands. Once a rural fishing community, it now attracts tourists on day boat trips.
That’s because Aoshima is also known as Cat Island, where feral felines outnumber humans.
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Several Japanese media outlets now report that the island’s human population is six, who help to look after around 100 cats.
The cats were introduced to the island (which was a sardine fishing village) in the twentieth century to catch rodents, but they remained on the island and reproduced. Over time, the human population on Aoshima has decreased due to the decline of the fishing industry and more people settling on the mainland.
The consequences of the island’s cat population on other wildlife are unclear.
The cats were genetically profiled and the results were published in 2023. Researchers revealed that the cats populating Aoshima were significantly different from that of the populations of the port cities surrounding the island.
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Aoshima’s cats have one of the highest frequencies of the O allele observed in Japan, which makes it likely that the original group of cats introduced to the island had a high frequency of O allele carriers – perhaps also explaining why so many of the cats are red and tortoiseshell.
A mass neutering programme was set up in 2018 to curb the cat population – especially since that without humans, it is unlikely that they would survive on the island. The future of Cat Island therefore remains uncertain.
