While Morpheus is held captive, Agent Smith tells him the following:
I’d like to share a revelation that I’ve had during my time here. It came to me when I tried to classify your species. I realized that you’re not actually mammals. Every mammal on this planet instinctively develops a natural equilibrium with the surrounding environment, but you humans do not. You move to an area, and you multiply, and multiply, until every natural resource 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. A virus. Human beings are a disease, a cancer of this planet, you are a plague, and we are the cure.
I hate this place. This zoo. This prison. This reality, whatever you want to call it, I can’t stand it any longer. It’s the smell, if there is such a thing. I feel saturated by it. I can taste your stink and every time I do, I fear that I’ve somehow been infected by it.
This comes, of course, from a piece of software representing the machines who view humans as essentially batteries and feed the liquidated dead to the living. It is perhaps not the best anthropological foundation to adopt.