Bower + Ionic: Reduntant dependencies

When starting a new project with ionic 1.2.1, I realized that the dependancy of ionic (angular, angular-animate, angular-sanitize and angular-ui-router) are already downloaded into the folder “www\lib\ionic\js”, and everything is working perfectly.

But when I run the command “bower install” is carried out the download again these dependencies, but now, directly inside the folder “www\lib” … making it redundant. I could not figure out why this happens.