The document describes key facts about black widow spiders, including that they have a shiny black body, eight legs, and marks on their backs. They grow up to 1cm long and live in North America. Black widows eat other insects and spiders caught in their strong webs, and females can lay up to 400 eggs at a time. Their legs are coated to avoid getting stuck in their own webs, and they are the most poisonous spider in North America.