Not sure if anyone mentioned this earlier but....
it helps to take a bath (and/or change your clothes) right before you go hunting.
(Especially if you are about to go hunt some
Legendary animals.)
Because when you are out hunting & using 'Eagle Vision'... you can see a (yellow) trail of your own body odor, which animals can detect, if they are downwind of you. So, the longer you go without taking a bath... the more INTENSE your own body odor trail becomes... which in turn, makes it harder to hunt... because the animals will detect your presence quicker (and from farther away) and just keep running away from you.