It seems as if animals might naturally have 'strangers'. But friendship?

It's difficult to imagine a third animal party stepping in; at least one which isn't dominant.

Is there a sense in which animals are ever expected to answer for anything?

Coming when called, and answering to a name, are not the same.

Though few will do so, it's possible not to give your pet a name. Not giving a child a name is unthinkable.

You get to call pets whatever you want. They don't call you anything.

Animals will kill things and eat them. Or sometimes just kill them. Like it's something to do.

We say hello to animals, but they seem to have no use for our goodbyes.

When pets enter the room we don't think, there's an animal in the room! (But there are people with exotic pets.)

But there are plenty of places where we will say, 'How did a dog get in here?!'.