When I first came to Japan, I thought, "Where are all the animals?" Japan doesn't seem to have the small urban-adapted wildlife like we have in the United States, such as squirrels, raccoons, chipmunks or even very many birds. Other than the City Mouse, animals just don't seem to move to the cities here. Less opportunity, I guess.
Even in the countryside, there is a distinct lack of road kill. At home, common road fare is rabbits, possums and prairie dogs. Even on the small island where I live in the countryside, the wildlife is limited to stray cats and aquarium fish. After 12 years of living in Japan, the only animals I've seen in the wild are weasels and crows. A few years ago some deer swam out to our island from the mainland, but apparently the accommodations weren't good enough, as they didn't stay long.
I've also heard that wild boars used to swim from island to island off Onomichi in Hiroshima Prefecture. The wild boars swam out to steal "mikan" oranges from the orchards on the islands. They'd leave a path of rinds where they had peeled the oranges before eating them. But now the wild boars no longer swim out to the islands. Instead, they walk across the new bridge. What wildlife Japan does have is getting lazy.