Scientists have discovered that sea otters can get the flu — and not just any flu, either. According to the Smithsonian, these mammals are the world's newest carriers of H1N1, the flu strain that lead to a human pandemic back in 2009. And, according to a study published in Emerging and Infectious Diseases, scientists have no idea how these Northern sea otters caught it.

Over 70 percent of the otters tested positive for H1N1

In 2009, H1N1 spread globally in humans for the first time, and the strain has stuck around ever since. But only certain animals — animals such as pigs, turkeys, ferrets, elephant seals, and cats — are known carriers of H1N1. So, when researchers realized that over 70 percent of the sea otters they were sampling along the Washington state coast were testing positive for H1N1, they were more than a little surprised — especially given that otters have never been affected by human influenza viruses before.

The scientists hypothesize that the otters might have caught H1N1 from elephant seals, the only other marine mammal that can carry this strain, the Smithsonian reports. But researchers readily admit that this is just speculation. They will need to do a lot more research before they can figure out how the animals caught this flu. So far, the otters aren't showing signs of illness, but scientists want to be sure that it's not affecting their populations. Perhaps more importantly, however, biologists need to figure how this new carrier is affecting the ecosystems in which it lives.