OK, a logo can be a mascot....but isn't necessarily a mascot. A logo can be letters, symbols, objects, etc....
A Mascot, however, is more defined. It is a person, animal, object, etc that defines a group of people or persons. It is something that represents these people. Therefore, the Sioux image, IS a mascot, and can be a logo at the same time. The Sioux qualities that represent UND are the past history of the Sioux people, the proud people that lived in this area long before. We don't need some white guy with an indian costume jumping around like Illinois or FSU... Yeah, it's a "mascot" but that's not what defines a mascot.
The Sioux image and idea that we are proud to know is our Mascot.
Don't limit the idea of a mascot as something that runs around a stadium or building cheering people up, cuz that's not what a mascot is.