There have been many colorful posts on C&R. Intermediate the catch and release is the problematic study phase. In lieu of a baby thermometer, I recommend a non-contact infrared heat gun.
The 'hole' scenario is a point location and there are many points to guess at. You need to consider the 'Goldilocks factor: too shallow, too deep, just right'. The water table may spank you big time. There is a factoid about digging a hole: " it is the only job that you will have where you start out at the top".
I am surprised that caves / abandoned mines / lava tubes were not suggested. Used by humans and animals for millions of years. Digging not required ( lets Norseman off the hook ). I avoid caves and abandoned mines for safety reasons but unfortunately, a fungus is among us. The cave approach is shut down due to bat WNS. The White Nose Syndrome in Washington State has the fungus in 10 counties and 5 counties have confirmed cases of WNS in bats. Check with your fish & wildlife dept. to determine the status of your caves.
Examine the percentages. Number of Sasquatch that have fallen into holes. Number of Sasquatch that visit campsites and leave hand prints, crush tents, sniff tents, steal food / dump out coolers, make noises, watch campfires, reach through open portals of vehicles and generally scare the campers.
In campsite mode, one can use a non-contact IR heat gun from the confines of your tent /blind / vehicle for your heat studies.
Funny how they have to go where humans are to spy on us and teach the young ones about human behavior and to avoid us.