These spiders live in Central America and South America. They hide in the daytime and walk around looking for food at night. So in English they are called 'wandering spiders'. There are several species, and only "Phoneutria fera" can kill healthy adult humans. People who get bitten by Phoneutria spiders can be given an antivenom. In any event, their degree of toxicity has been challenged. The spiders may be able to control the amount of venom they inject.