A collection of over 40,000 trees in rural Utah is the world’s largest single organism, having all descended from a single seedling. But that’s not all: According to a team of researchers, the grove—collectively known as Pando—may also be the world’s oldest living organism. Though it consists of over 40,000 individual trees, Pando is a single organism that originated from a single seed.

Exactly when that seed sprouted, though, remains up in the air. According to a team that recently estimated the organism’s age, Pando is between 16,000 to 80,000 years old. In other words, sometime between the glaciers receding from Manhattan and the last time the Tsuchinshan-ATLAS comet passed through Earth’s skies , a seedling in what would become Utah began to form Pando.

The team’s research on Pando is not yet peer reviewed and is hosted on the preprint server bioRxiv. The grove that constitutes Pando is the largest, most dense organism yet known, clocking in at nearly 13 million pounds (5.9 million kilograms) and covering 106 acres (43 hectares), according to the U.

S. Forest Service . Based on the recent research, Pando may have already been 40,000 years old when Neanderthals disappeared from the fossil record about 40,000 years ago.

“We studied a very iconic organism, whose size has made us wonder about its evolution in time and space,” said Rozenn Pineau, a researcher at the University of Chicago and lead author of the study, in an email to Gizmodo. “We expected cl.