It was USAF Combat Survival School, mandatory for aircrews...
When I attended as part of my aircrew survival training, the practical field course was being taught in the Colville National Forest - due North of Spokane and Fairchild AFB, home of the 336th Combat Training Group and 22nd Training Squadron.
More here:
http://public.fairchild.amc.af.mil/library/factsheets/factsheet.asp?id=3771
Regardless, a snare is considered a very efficient means to gather protein in a combat survival situation. It also is energy-efficient for the trapper/survivalist, because he can set it and simply return at a later time to see what he's caught, vs. babysitting or running down the animal. You don't want that kind of visibility in your combat survival situation, either. Remove the combat aspect of the survival situation from the picture, and you still have a big protein return for a minimal energy investment on the part of the survivalist.
The intent is to catch smaller critters like rabbits and squirrels. A gentleman's agreement between the Dept. of Interior and the USAF Survival School at Fairchild allowed the taking of deer in Colville National Forest, contingent upon complete use of the deer by the school, and that there wouldn't be a trail of discarded deer carcasses for rangers and park visitors to see once the agreement went into effect.
Suffice it to say, not many deer were taken by the school, and I doubt many were taken even after I graduated. Deer aren't so stupid as to normally be caught by snares, we were just good at emplacing ours and camouflaging it. One rule after that part of the combat survival training ended was that we were to locate ALL of our snares and remove them to prevent mayhem after our departure.
(Side note: We were instructed to avoid contact with the public visitors of the national forest, and not to mooch, leech, beg, borrow, or steal foodstuffs and conveyance while undergoing training. Evidently some industrious survival students had talked the Clark Griswald Family in giving them a station wagon ride to their rally point during the evasion portion of the training, so it was now taboo. I wondered afterwards how many civilian campers got spooked by camouflaged USAF aircrews stealthily moving through the forest in their vicinity...)
We used brass wire for our snares, and a couple students in my flight decided to braid their wires to make a stronger snare, attached to a log near a visible deer trail. My first thoughts were that we were going to catch a badger or wolverine, and that would be a lot of fun dispatching an angry version of either.
It was a whitetail doe, and the noise she made when snared was enough for us to hear from our improvised parachute cloth shelters 50-100 yards away. By virtue of my Wisconsin upbringing, I was a rifle hunter, not a big trapper, so the sight of such an animal thrashing around with one leg securely fastened to a log saddened me a bit, but we had been existing on about 800 calories a day, scrounging for wild strawberries and field mice, squirrels, and one issued rabbit to supplement a couple MREs and whatever water we could find. It was a no-brainer, we trapped her, and we were going to eat her.
If nobody here has seen a USAF issued crash axe, it looks like a handheld hatchet, with a curved serrated edge on one side, and a big marlinspike looking thing on the other side. The technique for exiting a mangled, post-crash aircraft is to use the spike to open a hole in the aluminum fuselage from inside out, then use the serrated axe edge like a can opener to cut an upside-down "U" in the fuselage, folding the aluminum down and creating an exit from the wreck. (Yeah, this is done while the plane is burning, smoke is burning your lungs and eyes, you've got one good hand left, etc.)
My personal example is bright red, but look at the crash axe on the right - that's what I have and what I used on the deer:
It was not pretty - she was worn out and panicked from thrashing with the snare, big scared eyes, and all of a sudden a bunch of hungry guys in dirty flightsuits and BDU's converge on her. As a 6-foot tall deer hunter I was "volunteered" to be the executioner. I said a silent prayer, then used the spike end of the axe, which measures all of about 3.5" in length, and swung as hard as I could in the vicinity of her ear - I figured the bone there was thinnest and I wasn't about to take my survival knife and try to slit her throat. I wanted instantaneous trauma that would minimize additional suffering, AND I had an audience. I'm not going to get any more graphic than saying it took several swings to get the job done.
The instructor said I did a good job, but I field-dressed the doe just like I would during Wisconsin deer season. The difference was that the instructor was making me stop partway through the procedure to explain what I was doing, and also make me conserve things I normally wouldn't. Organ meats like the heart and liver I would normally take, but the instructor took other items, (brain and marrow are good sources of protein, but that was before the current CWD scare, too) leaving a very small gut pile that we eventually buried to minimize our footprint in the forest. The whole flight got busy quartering the deer into portions small enough for each person to carry. There was a bit of a heated discussion as to who would keep the cape, but we eventually agreed that the school would be best served by it.
We had a sister flight in the woods with us that week, not more than a kilometer or two from our own location. The instructor didn't want us to get greedy and mess up our scrounging practice, so the venison was shared via the other instructors to the sister flight, complements of the WC-135 guy with the crash axe. I had some boullion cubes in my survival pack, so I rightfully claimed the tenderloin as mine, and with crushed boullion cubes and a little water sealed it in a hasty aluminum foil pouch, then placed it in the hottest part of the campfire until done. Truthfully, I don't think I've ever tasted better venison before or since then.