Caribou hitch a ride on an ice chunk in the Yukon River near Circle, Alaska. (AP Photo/Alaska Department of Homeland Security and Emergency Management, Claude Denver)

Thanks a lot, caribou.

In a study published Tuesday in the Proceedings of the National Academy of Sciences, researchers report using DNA preserved in vintage caribou poo to recreate a unique virus.

The DNA was found in a drilled ice core that contained thousands of years worth of caribou defecation. Researchers saw that it resembled modern geminiviruses --which infect plants -- but didn't recognize the virus itself.

Once they copied the virus, they introduced it to a species of tobacco plant vulnerable to many viral infections. Sure enough, the virus successfully infected the plant's leaves. Researchers believe it probably came from either a plant eaten by the caribou or an insect attracted to its feces.

There may be a downside to viruses that survive well in poop-sicles. As climate change melts more and more of this ancient permafrost, there's no telling what microbes might be released -- and some of them might remain infectious.

"There's a theoretical risk of this, and we know that the nucleic acid of the virus was in great shape in our sample,"study author Eric Delwart of the University of California told New Scientist. "But old viruses could only re-emerge if they have significant advantages over the countless perfect viruses we have at present."

So we probably don't have to worry too much about other viruses from that time period emerging in full-force from caribou poo.