Well.... I don't know. I grew up in the woods and I can tell you that the more time you spend out there the more you blend in, the more in tune you become. You see things and smell things and sense things that a city slicker does not. When I was in my teens I saw a large foot print about two miles from my home. I was always in the woods, sometimes at night for fun. So this area where I saw the foot print was along a game trail that ran through the woods and crossed a creek into a bean field. Any animal or human had two choices, follow the creek around or cross over the field and back into the cover. What was also interesting was the placement of the foot print. It was exactly in the center of the creek which was frozen at the time. The creek was about 12-15 foot wide at this point and more shallow. It was the best place to cross as the ice was sure to be frozen, which is why all the animals used it. Once crossing the ice you had to climb a 5 foot bank to the field. I have long legs and covered the area in about 5 or 6 normal steps and 3 looong steps. When I saw the print, I immediately though " foot print " not if I use my imagination it COULD BE A FOOT PRINT. I wear a size 10 boot, and the foot print was slightly bigger. As mentioned it was dead center of the creek, so I could imagine whatever made the print ( it that is what it was ) stood at the south bank and took 1 step to the center and the next step hit the dirt bank. Being a good distance from home I was a little concerned, but not too scared. I certainly didn't feel like I was being watched, and the print had frozen in the slush from the day before so I figured it was gone, whatever it was. So that's what I saw. I have no reason to lie.
I know there has not been any verified evidence found. I will say this, in the city where I live the poulation is about 500,00. Around 5 or 6 years ago a cougar was killed on a major interstate. It was right in the middle of the city, using ditches and drainage areas to move around without being seen. Also to the north of me there are verified cougar sightings. What is interesting is that for years the Conservation Dept. denied the existence of cougars. Black bears too for that matter. Large animals can hide quite easily when they need too. I know of a spot in the city, right in a suburb where 30-50 deer regularly hide. If they don't want to be seen you won't see them. I can't say that out in a National Forrest of a millions of acres there isn't a primate hiding. I have been in areas where you literally cannot see more than 20' into the woods. Traveling through those areas is hellish and I love the woods. If there was an 800 pound Grizzly bear 25 feet away, you COULD NOT SEE IT. So I can't say that there isn't something out there, there are still some wild places. Just for something to think about, the Congo swamp is about the size of Florida, and only about 10% has been explored to this day. Who knows what is out there.
