glacier mouse

plural glacier mice

1. plural normallyA ball of moss, often surrounding a rock, that moves across a glacier.

   Glacier mice can be composed of different moss species.

   2020 May 22, Nell Greenfieldboyce, “Herd Of Fuzzy Green 'Glacier Mice' Baffles Scientists”, in NPR

   2 more examples

   I call these mossy balls Jökla-mýs, literally "glacier mice," and you will have noted, Sir, that rolling stones can gather moss.

   1950, Jón Eythórsson, “Jökla-mýs”, in Journal of Glaciology, volume 1, number 9, →DOI, page 503

   Such glacier mice are more or less spheroidal mosses which lie unattached on the ice surface.

   2014, James H. Dickson, Robert E. Johnson, “Mosses and the beginning of plant succession on the Walker Glacier, southeastern Alaska”, in Lindbergia, volume 37, number 2, →DOI, pages 60–65