Long ago, I once taught a course in a hotel that also housed a “disco”, which if you remember what they were, gives you an idea of how long ago it was! One evening after class, a student talked the DJ into plugging the video cable into the infrared imager we were using and suddenly there were about 100 large video screens sporting images of hot, sweaty people dancing. A bit of thermal wild life!
Thermographers often look for other kinds of wildlife as well, but they are typically much more difficult to see. I remember looking at an owl once, perched about ten feet away on a cold, windy day. I could not see it at all! The feathers were all puffed out, the better to keep the bird warm, and the wind whisked away the little heat that might have revealed the bird. I was stunned at how useless my technological “advantage” was.
Since then, I’ve had many opportunities to view other types of warm-blooded wildlife and am often impressed with how challenging it is to see them in their habitat. First, their fur or feathers do a pretty good job of containing their body heat. Often the best place to detect these creatures is either straight on to their front or from behind. In both places the fur is less thick and the blood vessels are often closer to the surface of the skin.
When animals hide in brush, as they do frequently, finding their thermal signatures is even more challenging. As is often the case when trying to see them with our eyes, especially at a distance, the combination of brush—at various temperatures itself—and fur/feathers makes thermal detection much more difficult than might be imagined.
The group of young biologists conducting fieldwork demonstrates this as well. Dressed for night work in a heavily wooded area, they are easy to see only because of their faces. The turkeys shown are also an exception as they were moving across an open area and were quite easy to spot.
Sometimes it all seems so simple. Hey, probably any fool could find a turkey. Isn’t that so often the case with our more regular uses of the technology? How often have I pointed out the one hot wire in a bundle of wires in an electrical cabinet. It is at that point that the electrician says “Yes, that wire is a bit toasted!”
Next week, we’ll talk about toasted wires and roasted turkeys! Until then why not go out and see what kind of wildlife you can spot with your imaging system.
John Snell—The Snell Group, a Fluke Thermal Imaging Blog content partner