A search engine spider is a program that works behind the scenes to deliver up-to-date Web search results to users through a search engine. The search engine spider can work continuously or respond to user events. Typically, the search engine spider uses specific and ordered methods to scan Web text and index pages for their search engine rankings.
Spiders are also called Google bot, this is a search engine automated programs that are crawl your content from web page and store as an information in search results
However, a spider is automated software that finds and crawls over websites on the internet for the purpose of indexing pages. These spiders are also known as "bots". Search engines use this information when performing their searches