White-tailed ptarmigan and development of the chicks. This suggests that the hens' food calls assist in enhancing survival rates of juvenile ptarmigans. The young birds remain with their mother throughout the summer and autumn season. The white-tailed ptarmigan is well-camouflaged when on the ground. In his pioneering 1909 book on the subject, "Concealing-Coloration in the Animal Kingdom", the American artist Abbott Thayer wrote: The white-tailed ptarmigan has feathers located on its feet to serve as protection from the extreme cold often experienced in the alpine tundra environment. In addition, these birds have feathers around their nostrils to warm the air prior to
Winter white dwarf hamster the body weight ranges from , and in females, . In human care, they are slightly heavier. The average lifespan of the Winter white hamster is one to three years in captivity, though they can live longer. In the wild, they are known to live as little as one year. In summer, the fur of the Winter white hamster on the back changes from ash-grey to dark brown, or sometimes pale brown with a tint. The face changes to grey or brown, while the mouth area, the whisker area, and the ears are slightly brighter. The outer ears and the