I used World Book Online For Kids to look up squirrel.  I liked the "tools" that were available to the user - email, print, and the ability to hear text read out loud (very useful to the patron who is hard of hearing).  This gave quite a bit of information on what the squirrel eats, body features, and habitats. 

World Book Online offers different interfaces for varying age levels (use by kids and adults).  Makes research fun with the use of videos and sound.

In "Info Finder," you can do an "advanced search."  This allows you to look at various texts such as research guides, special reports, websites.  You can search a list of encyclopedia articles on "squirrels."  You can look at dictionary, maps, tables, pictures, research guides.  You can "limit" during your searches.  The left side breaks down the "squirrel" in many subcategories.  This is great for the older student who really needs to research his subject and use a variety of sources.