When did humans start getting the common cold?

Most people catch the common cold at least once a year, making the seasonal sniffles a staple of the human experience. But when in Homo sapiens' history did people first start catching the common cold? 

The question is difficult to answer, in part because many viruses cause colds and few of them preserve well in human remains. But it's possible that some of the earliest Homo sapiens were catching colds at least 300,000 years ago, the time the oldest archaeological evidence of our species dates to.

"Common cold" is an umbrella term for a group of respiratory infections that tend to be mild in people with Healthy immune systems. Rhinoviruses, coronaviruses and respiratory syncytial virus (RSV) are often to blame. But before these pathogens began to spread between people, humans probably acquired them from other vertebrates.

"Living in close proximity to Animals is a surefire way to be exposed to new viruses and to get the repeated exposure that could result in it becoming a human endemic virus," Joel Wertheim, an evolutionary virologist at the University of California, San Diego, told Live Science. 

Related: Why do people get sick when the seasons change?

Usually, when an animal virus jumps into humans, it fails to establish an infection because it's not adapted to its new host. However, a virus will occasionally possess the right set of genes to make the leap successfully and even spread among humans. That's how the viruses behind COVID-19 and "swine flu" emerged, for example. 

Scientists have different hypotheses as to when cold viruses first took off, placing their onset at vastly different points on the human timeline. Some researchers think the viruses could have started spreading from animals to humans at the dawn of human civilization — approximately 5,000 to 6,000 years ago. Humans were starting to live in close quarters where pathogens could spread easily, and they began farming animals swarming with viruses.