The Matrix-
The other night my buddy and I were driving around trying to find a place to enjoy the genius weather that night and have a couple of drinks. Turned out every place we went to everyone had the same idea, tons of goons in every bar, sitting outside and doing what I should be doing. So we decided to go back to his, pop open some Hennesey and JD and do it up. I am starting to really enjoy Hennesey once I learnt that the trick is to take small sips, roll it around under your tounge and smoke a tasty monte cristo fine cut. It sounds quite regal but it really is quite slick once you get accustomed to the jet fuel taste.
Anyways, we ended up getting progressively more and more sloshed and then I mentioned for the millionth time how unbelieveably epic all three matrix movies were. He whole heartedly agreed and we proceeded to talk about it again for the next two hours, without interruption.
We tried to look at it objectively this time and tried to figure out if the Wachowski brothers actually understood the mega implications of this piece of cinematic history. The core premise of these movies is about a dual reality, a computer simulation that has fooled the majority of the human population. But once you start to ponder the process by which this program works is where the infinte loops kick in. One of the aspects which confused me is that the program only uses humans as their energy source after the humans cut off their primary source of energy, the sun. All of this is much better explained in the Animatrix episode titled The Second Renaissance part 1.
Why is it they do not use the many other forms of thermal, kinetic and electric energy that can be sourced from all the animals (and plants) on earth. We realized that a being needs to be concious to emit a certain level of energy which really explained why there was in fact a simulation to make humans believe that they were in modern day reality. Why not just have humans as fuel cells without implementing another reality for them? Wouldn't that save time and evergy for the machines? The simple answer is: a comatose patient usually dies within a week and his/her energy output is minimal as there is minimal brain or body activity. Radiation is the emission of heat from the body in the form of waves, a process responsible for half of all heat lost by the body. For this an intake of glucose and oxygen is needed which comatose patients are capable of, but the distribution of these things are (depending on what stage of coma) inefficient.
This is why everyone in the matrix had to be in a constant state of awareness of reality, because if they weren't they would literally be as useful as a dead battery.
It is the similar for animals. As far as we know they do not have a conscience. Again this point has been debated throughout the centuries but from a quantitative and qualitative point of view, it would seem as if they do not really have an defined conscience i.e. the knowledge of ones thoughts and actions and the reprucussions of those actions, both in the long and short term. In reference to the matrix, they would not be effective sources of energy as the matrix could not write a program for a monkey, elephant or a platypus for them to believe they are in their own reality whilst delivering the same output of energy in the machine world.
Another reason that humans are cultivated for their energy is because they multiply exponentionally. It is relatively easy for the machines to fertilize a human egg and incubate it to maturity without much effort. Agent Smith tears this shit apart with this legendary quote:

'I would like to share a revelation with you, that I had, during my time here. It came to me when I was trying to classify your species. I found out that you're not actually mammals. Every mammal on this planet instinctively develops a natural equilibrium with its surrounding enviroment. But you humans do not. Instead, you multiply, until every living thing is consumed. The only way you can survive is to spread to another area. There is another organism on this planet, that follows the same pattern, do you know what it is? A virus. You humans are a disease, a cancer on this earth, you're a plague. And we, are the cure.'
Pure genius. It makes sense why the machines would manufacture and use our energy instead of any other living organism. A lot more is going to be said about these ideas in the coming weeks. Any valid commentary is welcome.

  ¶ 3:26 AM