Japan has over 400 species of spiders, but only a few are considered medically significant. While some spiders can bite humans, none of them are deadly or cause severe reactions. The huntsman spider, orb-weaver spider, wolf spider, and jumping spider are common in Japan but not harmful to humans. If bitten by a spider, wash the affected area with soap and water and apply a cold compress to reduce swelling. Other dangerous animals in Japan include the Japanese hornet, pit viper, and Japanese macaque monkey.