In The Matrix, Hugo Weaving's sinuous and serpentine Agent Smith makes an argument that human beings aren't actually mammals. They are a virus.
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 and 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 and 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.
If Agent Smith were a data visualization editor, he might have come up with a map of global population that looks like this: a planet dripping with virulent human ooze.
Designed by Reddit map-porn maker Restricted Data, the "Human Ooze" infographic imagines the world's population density on various longitudes and latitudes as literal drips. The data is derived from the Oak Ridge National Laboratory LandScan database, and shows estimated population density over a 24-hour period, indicated in both color and length of each "drip."
One important thing to realize about the Human Ooze map is that it's based on population density, not city population. In other words, the more densely packed a city is with humans, the drippier it appears on the map. In this paradigm, Mexico City, which is around 2,000 square kilometers, would not be as dense as Mumbai, which has a population of 14 million squeezed into only 480 square kilometers.
Whether or not humans are a virus or not, the map is certainly an interesting one to behold, with various cities in Asia, the Mediterranean, and the East and West Coasts of the United States so filled with people that they seem set to literally drip off the map and onto the floor. If Agent Smith looked at this, he'd have a panic attack.