Studying Pacific pocket mice in their habitat is no easy task. The mice are tiny, and they blend into their surroundings. They burrow. And to top it all off, they are nocturnal. So how do researchers study them? Where there's a will, there's a way! They catch up the mice and inject bands of nontoxic, fluorescent, colored dye into their tails, different colors and patterns for different mice. Then the researchers turn off their head lamps, settle down, and wait for the light show! As the mice go about their nocturnal habits, the researchers can see the dye and track who is doing what and going where.