More than 120 feral cats live on Aoshima Island , where they have just a handful of cats for company . The cats were originally brought to the remote Japanese island to kill mice living on fishermen 's boats . Most of the local residents left the Island to settle on mainland Japan after the Second World War . But the feral population grew and have since multiplied - meaning they now massively outnumber humans .
More than 120 feral cats live on Aoshima Island , where they have just a handful of humans for company . The cats were originally brought to the remote Japanese island to kill mice living on fishermen 's boats . Most of the local residents left Aoshima Island to work on mainland Japan after the Second World War . But the cat population stayed and have since multiplied - meaning they now massively outnumber humans .