Ecomodded: Sorry buddy, it's CRAZY cold outside right now even during the day. I'm NOT going outside at night in this weather. Also, I don't have a cat or a dog (wife has allergies.)
However, I did play around with the camera last night (indoors) a little bit in the dark.
Here's a photo of my four-year-old daughter, taken in the dark.
The thermal imager is pretty low res (I think it's 120x80 or something weird like that.) So without the visible light camera creating the edges in the image, the thermal alone looks somewhat blurry. This was indoors, so the walls and furniture around her held some heat, otherwise the background would be black or very dark. Just based on this, I think that the camera would do a fine job of seeing objects outside in the dark.
Also, keep in mind that this camera is PASSIVE infrared. It does NOT have any infrared LEDs on the front of it or anything else. It simply senses infrared heat emitted from objects. So, theoretically, it should be able to see a dog 100 feet away in pure blackness.
Pinballlooking: I agree. If I didn't already have the iPhone 5, I wouldn't have purchased one just to use the FLIR ONE thermal camera. But, I already had the phone, and the camera looked pretty slick. Lots of other people are excited about the SEEK camera for Android.
http://obtain.thermal.com/product-p/uw-aaa.htm