You can also use iPhoto which comes with the computer (under Applications). There is also a program called Aperture which is available on the Mac App Store which has extra features that can be quite useful. It is similar to Adobe Lightroom... both have lots of extra features which are especially helpful when working with RAW photos.
Most DSLR now use a form of flash drive. It doesn't mount like a disc drive.. so you would need to open an application to see your images. I know it's crazy, especially when you try to update your camera.