Well this is how they spend their sniffing hours. Smelling many different things.
Mulder and Scully say : It's because we're so curious.
Their P.I. skills include sniffing everything even the air.
Look at them. It's extremely cute especially when they sniff the camera
Click here to watch them sniff the world http://www.youtube.com/watch?v=Xv_Rl42PJmk