I found the rotifer in early March, still winter here. I was bored and stuck at home doing school and decided to cut some lichens off the sidewalk in front of our house. I think there was still snow on the lawn. I’m not sure where you are or how cold it gets there; here in southern Ontario we do get warm spells off and on throughout the winter and e.g. invertebrates will still come up to the surface. But I imagine even below freezing temperatures there are things dormant in lichen and moss that will come back to life once they’re brought inside and start to thaw.