The snow of an arctic winter makes getting around a challenge for the ptarmigan,
which spends most of its time walking around on the surface of the ground, searching
for plants. In order to prevent itself from sinking, the ptarmigan grows extra
long claws on its toes each winter. These claws help it to get a grip on icy
surfaces, and act as snowshoes in softer areas. In the spring, it sheds the
long claws and grows a shorter set!
The feet of a ptarmigan are also feathered, which, in combination with the long claws, increase their surface area fourfold. These extra trappings act as snowshoes, reducing the depth that the ptarmigan sinks into the snow by fifty percent.