Some people like to keep spiders as pets,particularly tarantulas,which are native to North America and can live for up to twenty-five years.Most people,on the other hand,do not like touching spiders,and a significant number of people are afraid of them,mainly because of their poison.However,despite their bad reputation,only thirty of the 37000 known species of spiders are deadly to humans.Spiders actually provide benefits to humans,by catching and eating harmful insects such as flies and mosquitoes.