If you’ve had the opportunity to join us for a Glacier Hike, chances are you’ve seen a rock or two covered in greenish-orange moss somewhere out on the ice. You may have even been lucky enough to see a whole herd of them! Most people are astonished when they see these and are keen to find out exactly what they are. And what do we tell them? “They’re Glacier Mice!”
No, we’re not pulling your leg! More scientifically known as a glacier moss ball, scientists far and wide also call these anomalies glacier mice, or even moss cushions.
You’ve probably heard the old proverb “a rolling stone gathers no moss”. In the case of Glacier Mice, that’s wrong! If it didn’t rotate, the moss on the underside of the rock would die. Part of a study that took place on the Root Glacier actually tagged and tracked a whole herd of these rocks. Although we don’t perceive their movement, the study found that they traveled about an inch a day! But exactly how and why these mice migrate is still unknown.
The study on our furry friends that took place on the Root Glacier was published in May of 2020. You can read the full scientific report here. If you’d like a more fun-to-read summary of their study, you can read NPR’s interview with the scientists here.