Good question. I'll tell ya what I've read, heard or experienced on the subject.
A grizzly bear can smell you doing game chores on your kill from over 5 miles away and can be there to help within 15 minutes or so. Many of them are trained to come to the sound of a rifle shot.
A dog can smell drugs wrapped in plastic and buried in coffee. Bears and pigs have better noses than most dogs. Not sure about the cats.
Cut yourself and everything downwind knows about it.
I did an experiment once with some bacon grease, which is a fairly common odor on humans, and is also a fairly strong odor. Anyway, I placed some grease on plastic wrap and bundled it in a couple of layers. Then I put gloves on and placed it in a ziploc bag. Then I placed it in another ziploc, pushed the air out of it just like I did the first one and sealed it up. Then I placed the package in a tuperware container and sealed it just like you're supposed to. My wife is still pissed that the bear tore the container up to get at the grease. Maybe the bear smelled the grease when we cooked the bacon and started our way then. But I placed the container well away from camp and wedged it in the Y of a tree. The next afternoon I went over to check it out.
You might give it a try the next time you're out and about. Maybe if you draw all of the air out of the package and wrap it up a few times and place it in foil packet or something.
There are several articles that I've read on how to store food while in bear country (up a tree and away from camp) and how to dispose of garbage (bury about 200 yards upwind of camp). They say that the freeze dried foods may not attract bears or other predators to you, but I don't have any first hand experience with it.
Maybe someone can share what they know about it. My knowledge, other than my experiment is from reading the newspaper or listening to hunters stories round a fire or have read them in bowhunting magazines.
I wouldn't be one bit surprised if they smell human and come to see what goodies they got.
