Thanks for the help...iPhoto 11 on my Pro isn't recognizing the .nef file extension. Advice?

I'm importing photos from a Nikon d5200 in RAW format and iPhoto says it doesn't recognize that file extension (.nef). The movie files came off just fine. And when the initial window comes up in iPhoto asking if I want to import all photos or just the selected ones, I can see all the RAW file images as usual. They just won't import.