[Jensson]

Animals used to the winter survives being wet, at least large ones like moose, they fall through the ice from time to time and people help them up. Maybe lemmings are so small that it wasn't worth evolving it, but it seems like a big handicap since most animals needs to drink regularly even in the winter.

[ahoka]

Large ones have more heat reserve due to square-cube law: surface area increases less with volume.

[the_af]

Yeah, I think what I said applies to small animals like birds and rodents, creatures without large fat reserves.