@CoccoBill: A tame(d) animal is not the same as a domesticated species.

Quote Originally Posted by Savy View Post
Why are some animals so at home with living with humans whilst others are not? I can get why some wild animals are going to think you're a threat no matter what but when animals are brought up from birth to have humans why is this? Do they just develop a I'm going to ignore you/eat your face mechanic?
The domestication of a species happens over many generations, guided by human intervention and selective breeding.

Different animals were "first" to be domesticated by various cultures with various indigenous fauna. Livestock could be herded and penned, but those big impaling horns are dangerous. So breed the individuals with smallest horns until there are no more horns (modern cattle). You got them in pens, but they are terrified of humans and hard to manage... except for a couple of them, which are a tad more docile. So breed the more docile ones until the herd is no longer terrified of humans... or at least isn't behaving like they are. Etc.

Pets are in the fossil record as far back as any domesticated herd animals, if I remember my college anthropology right. Something about the oldest-known bone piles, where the bones are all from 1 species of herd animal, and were in use for generations, have humans and dog skeletons buried together near there. So it seems that some people had pet dogs in the earliest known herding communities.