BIOL 140 Lecture Notes - Lecture 21: Igloo, Rodent, Convergent Evolution
Document Summary
Europeans had basically wiped out beavers by the time they invaded america. Used beaver fur (felt) to make stovepipe hats. Dig up mud from the bottom of the pond. You can see all the twigs - not a fresh house. This means the rain has washed a lot of the mud away. If the roof were hot (insulated), there would not be snow on top of the roof. If this were an abandoned beaver house, the mud would have washed out, the snow would have fallen, the dark mud would have taken up heat from the sunlight, and the snow would have run off. When the house has 6-8 in of wet mud, that is good insulation. With beavers inside, they generate a lot of heat (igloo principle) There"s a hole at the very top of the house with hot air coming out. Beavers on the inside pushing out and beavers on the outside pushing in.
