The frigid cold and deep snow makes life in the tundra very difficult.
Animals are adapted to handle long, cold winters and to breed and raise young quickly in the summer.
Some have grown thick fur which turns white in the winter.
Mammals and birds have additional insulation from fat.
Others find a place to hibernate during the winter months b/c food is not abundant.
Reptiles & amphibians are few or absent b/c of extremely cold temp.