Replying...
Intro. You were a young child travelling with your family on a holiday. Along with the other 299 other passengers on the plane they died on impact leaving you the only survivor as a child. Over the years you become more like the feral beasts around and less human and as you didn't have have much vocabulary to start with you soon lost the ability to talk. In order to survive you watched other predatory animals hunt and become like them eating everything you can catch and hunt from rabbits to wild boars and more. You can even eat the most poisonous animals without problem since your body and immune system has become more tougher. You have picked up a sense that you don't recognise...is it food or something else (You can be make or female say at the start to set how you are presented in little or no ragged and torn clothing)

Forest survival

@Gordon