Japan has many “Cat Islands” which felines have taken over from humans. Or at least so it seems. Anyway, here are the the most well-known ones, to give you a (two) example(s).

Japan is definitely a country that adores cute “kawaii” things. And really, what is cuter than an island full of cats? The Japanese have created the expression Nekojima [猫島] (which literally translates to “island of cats”) for these special places, which stand as examples of the influence cats have in Japan.
Each island has its own unique story as to why it has become dominated by the furry felines. What can be said about all of them, however, is that although most cats on them remain feral, many locals continue to care for them. But, as the locals get older, and the cat population grows seemingly exponentially, these islands are literally being taken over by cats – especially that they usually have no predators on these islands, where dogs are also often banned.
Picture of the day: Welcome to Cat Island (@ Aoshima Island, southern Japan)
REUTERS/Thomas Peter pic.twitter.com/s4Na4KoX55
— euronews (@euronews) March 3, 2015
This often means that an island has more cats than people, and it can be hard for locals to take care of them all. As the number of cats grow and their presence becomes overwhelming, even more locals decide to leave for good.
Take Aoshima, for example, a 1 mile (1.6 km) long island in Ehime Prefecture, Japan. Here, cats have been reported 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.
However, as sardine fisheries depleted and jobs moved to cities, the human population has decreased drastically on Aoshima. There are currently only 6 human residents on the island and more than 100 cats that are fed by food donations from all over Japan. The felines also eat the rodents on the island and some food from visitors.
Aoshima lacks no furry backs when it comes to dinnertime

No one shall pass here unless food is given!

Anyone seen some fish in here?

Tashirojima, a small island in the Miyagi Prefecture, Japan, is another well-known example of a Japanese cat paradise. The residents here kept cats to chase mice away from their precious silk-worms, which they raised for their textiles. In 1602, all pet cats in Japan were freed by law to counter the rampant rodent population that threatened the precious silk-worm industry – hence Tashirojima’s thriving feral cat population.
Here, too, the cats are free to roam across the whole island and they are well taken care of by the small community. According to tradition, cats are considered to bring good luck and fortune and this luck doubles, when you feed them.
As in the case of Aoshima, however, the island’s luck hasn’t doubled though in terms of its ability to retain its residents. Due to the increasing number of cats and also for other reasons, many people have shunned the island, making its population fall from 1,000 to around 100. Some loyal islanders still remain though, to make sure the island is preserved and the cats are taken care of.
Cats are so revered here that there are even some cat shrines where you can worship them. But if you you decide to do just that and travel to the island, be careful when you attempt to feed them. Although the felines are used to humans fawning over them, you might actually attract a crowd if you open up a can of tuna.
On Tashirojima, you also bump into a cat every few feet or so

The island has a cat shrine where cats are worshipped while they watch you worshipping them

The cat figurines around the shrine come from cat worshippers watched by the worshipped cats

This place is indeed incredible
Sources: 1, 2, 3, 4, 5