The Story of Microbes Microbes are the oldest form of life on Earth. Some types have existed for billions of years. These single-cell organisms are invisible to the eye, but they can be seen with microscopes. Microbes live in the water you drink, the food you eat, and the air you breathe. Most microbes are helpful and some even essential, like the billions of microbes swimming in your intestines to help digest food and create the essential vitamins our bodies need.
Billions more live naturally in our skin, mouth, nose, teeth, throat, and urethra.
Humans, microbes, and other living creatures all share the environment and interact in ways that allow them to coexist. Microbes' mission in life is to reproduce and do whatever it takes to survive. They have the ability to evolve rapidly and can adapt to changing conditions, but where any particular microbe can live depends on its biological requirements. Some, like the hantavirus microbe, are limited to the habitat of the animals that carry them for part of their life cycle. Others are far more specialized and can survive in only one type of environment.