In the wilderness, anything non-human that moves, is on the menu. Pythons and rattlesnakes are a delicious treat. Any bird big enough to cook is on the menu. The only problem comes with plant identification. If you do not know which plants can harm you, don't eat any of them. Even when you can identify them(such as the little bitty wild potatoes), there could be food allergies that come into play, that you may not experience with food from a supermarket. With fungi, such as mushrooms and puffballs), it helps to know when they are of the proper ripeness. Just one puffball the size of a golf ball can stave hunger for a few hours.
Knowing how to survive is key. Watching out for dangerous humans is even more important. It's much easier to scare off a 900 pound grizzle, than it is to scare off a lunatic with a firearm.