We smell like carnivores (well, most of us do) since we eat meat. Thus, mammals with a good sense of smell, and who are herbivores (prey)* stay away. Also, if you look at an animal and move towards it, it show interest- most animals show interest when they want to eat you. 
I know that a very great many of the earlier posts have merit. Unfortunately modern sciences can not grasp the concepts which are evident in inherent behavior. The posts which referred to Darwin, Bears and bobcats failed to grasp an undeniable truth. Even in the quantum world “nothing can exist beyond contact with the observer.” Simply by observing the hypothesis even the unobserved changes. In this instance it is the animals behaviors.
To put it simply human instinct is an inherited trait (I use that word loosely.) The animals of the Galapago and the Tundra were unexposed to man and, as it is understood, they had no “immunities.” Every creature on this planet fears man for a good reason. We are THE apex predator. Only Polar Bears and Hippopotamus seek out man as an act of predation. One from lack of exposure and the other because we avoid them! Even sharks avoid us because we will hunt them out of existence with impunity! You don’t learn to avoid us out of sympathy, it is because we hunt in packs and we always hit our mark!
Keep in mind that Man did not carve out his place by sympathizing with his food and neither did the gray whale keep his by being curious. The gray whale isnt extinct because we stopped hunting them. And the bobcat stopped eating kangaroos because MAN started to protect them. Canine even became separate species because we chose to feed/breed certain traits.
I profess that that I have no place in the academic community, but even Einstein started out as a patent clerk.
Yes, Neptune83, humans are, indeed, badasses, and everyone in this (14-year-old) thread knows that. That’s not the question. The question is, how do animals know it?
Just guessing, but could it be that bobcats don’t eat kangaroos because they live on different continents?
cochrane, who has seen many bobcats in Arizona, but not one kangaroo.
Oh, and hippopotamuses don’t prey on people. They’re just highly territorial and quite easily pissed off.
Too true. I was thinking of the Darwin quote when I started reading this thread. The book it was in juxtaposed it with the quote from the earliest sailors to visit the Galapagos, where a bird would land on the officer’s arm to drink from the jug as he poured a drink of water. And a generation later, where the birds kept 6 to 10 feet or more away at least.
IMHO from what I’ve read, there are several mechanisms - for the smarter mammals there is learning. Cats (as mentioned) have to learn hunting skills from mama, although some is instinctive. They also learn to associate certain situations with danger.
I’m planning a trip to Africa in the near future, and one of the things that I’ve read about is how Jeeps and Land Cruisers meander all over without being perceived as threatening or as lunch. The explanation suggests this is because boxes on wheels spewing hot smoke with a writhing mass of arms and heads poking out is not recognized as a threat or a lunch by the local creatures. Presumably if we have too many cases of shooting Cecil the lion from a jeep, the local creatures will get the hint.
Birds and stupider animals have more difficult learning curves; in that case, I think it is an instinctive “skittishness” gene. As Silver S. mentions, there is a range of creatures whose skittishness in certain situations is dialed up or down by various degrees. When dialed too high, they miss out on meals by being jumpy. When dialed too low, they are meals. Presumably nature has evolved a means to fine-tune this very quickly - the gene determining skittish level is easily mutated, and so evolution has to constantly select for the right level - and can therefore adapt very easily.
Also consider human fear of snakes or spiders - generally fairly widespread. There is a certain level of fear or revulsion (although intelligence can overcome it) that is instinctual even in a “blank slate” mammal like ourselves.
Certainly consistent with my mom’s trip to Africa this past summer. A lioness rubbed right up against the side of her vehicle, so close that Mom (had she been insane) could have reached down and petted her.
Ha!
You’ve obviously never spent a summer evening in Northern Minnesota, when the mosquitoes come out.
My landlady Cherie breeds, raises, sells, and shows Samoyed dogs. Recently, a litter of three was born to a mother named Azure (nickname, “Z”). Z was not raised in Cherie’s loving home, and is quite hostile to most of the humans in the house when she’s in the whelping box area with her puppies.
So Z was given very limited time with the puppies after they were weaned, because Cherie didn’t want the puppies to learn that hostility from her.
On this subject I would appreciate confirmation and refutation of the claim that animals with binocular vision are usually but not always predatory animal, and that some animals will have a greater fear response in this case.
Unfortunately I was looking for modern info based on this theory but have come up empty. I doubt that it is a primary reason, but does seem to be a logical contributing factor.