Talking with a friend from Texas, where pretty much everything is lethal, we realized that there are very few dangerous animals in Japan. The two we could come up with are the mamushi (aka Japanese pit viper) and the oosuzumebachi (Japanese giant hornet). If you see either, run the other way. Particularly, the hornets will swarm you if you approach their nest (photo below - beautiful things but to be avoided). Inform authorities if you spot a nest, and they will have it removed. - William https://msp.c.yimg.jp/images/v2/tpvPBYOX1wpNVI1UoNSgEtrvL7k9lx2-zrymg9F6y1ursqxxTsl5BP2Ba6x0QDgcVrUD26EFn1N5mqbS0BPCBjj2Du3Z_QF9NwHIlrcrrZsl4QOzieU3ppfVKs4mvKsRp46v9zJBzQskIO8tldsG8kqtfFQue1tpO7x-quTKlISM6PuNDw-7_9DTxCOP6CaXg2TUWon14TQrPwboFlQOaA==/suzumebachi01.jpg?errorImage=false https://en.wikipedia.org/wiki/Mamushi https://ja.wikipedia.org/wiki/%E3%82%AA%E3%82%AA%E3%82%B9%E3%82%BA%E3%83%A1%E3%83%90%E3%83%81