According to Buddhism, what separates humans from animals? Philosophers throughout history have been trying to pin down what it exactly means to be human -  what it is that separates humans from (other) animals. 

Some have voted for our ability to make rational choices for the future - in a word the ability to intend; and then acting accordingly or contrary to our own better judgements. Some put emphasis on our capacity for language and communication by the use of signs/abstract representations. Another variety is about freedom of will as opposed to freedom of action. Humans, they say, has both. 

Others still said it has really nothing to do with our rationality, but rather that it has to do with the internal structure of our will. That is to say, humans can want (or not want) to want something. We can have desires about our desires. I can say "I want to eat cake, but I don't want to be fat and I don't want to be seen as a person who succumbs to temptations. Therefore I shall abstain." A cat can want to chase and kill a mouse, but the idea is that the cat doesn't have the ability to say "I'm hungry and want to catch a mouse and eat it, but I don't want to be that kind of cat. Therefore I shall abstain."

How is this in Buddhism? What makes us human, what separates us from animals? Is it our capacity to understand/see that samsara is suffering? Is it our ability to see emptiness and dependent arising? Our capacity to be freed from suffering? Is it our rationality? Is this the same in all traditions?
According to Buddhism there 31 planes of existance out of one which is the animal kingdom.

Your next birth is decided by the last thought moment where you remeber a recent or grave act of Karma which you have performed. So what decides or separates us from animals the Karma which decided our birth.