Well, Kidder isn't technically ours. She belongs to a friend of mine and we are actually watching her for a year or so while my friend finishes her doctorate program. Kidder is a rat terrier and is about 2 years old. For the past few weeks or so she has been running outside (through her doggie door) whenever Geoff or I come home. We had no idea why she was doing this, so I decided to watch when I was home and Geoff came through the door. As soon as Geoff opened the door Kidder ran out to the back yard, headed left, jumped and sniffed all along the left side, the back wall, then the right wall of the yard before coming back in. She was doing a perimeter check! I think it's so funny! As you can see she's not very big, so I don't know what she'd do if she actually ran into a real threat! She's really friendly, too, and would probably lick someone before she bit them!