60 THE SPECIES— ITS TAXONOMY, RANGE, BIOLOGY, & ECONOMIC IMPORTANCE 



The feathers of a female grouse (teleoptiles and seniiplunies) were counted as they were 

 plucked and found to number 4,342*. In this species there are ten primaries and about 

 15 secondaries. The tail is normally composed of 18 but from 16 to 20 have been recorded. 



Each year grouse grow a series of rod-like appendages as a fringe along the sides of the toes 

 in the fall and shed them the following spring. The bird is thus provided with "snowshoes" 

 for the winter. These rods are derived from the skin and are thus closely allied to the 

 feathers. 



PHYSIOLOGY'^ 



When winter comes man puts on heavier clothing and lights a fire in his furnace. Many 

 northern mammals grow a thicker coat of hair or go into hibernation. Grouse seek shelter 

 in thick evergreen clumps and fluff out their feathers to provide insulating air spaces. Main- 

 tenance of body temperature is of paramount importance to the well-being of all warm-blooded 

 animals. 



Yet means of regulating heat loss represent oiilv mif side of the picture. The manufacture 

 of heat through the burning of food materiuls ii' the ImkU must also be carried on. Unless 

 the two are suitably coordinated an animal cannot survive long. 



One should realize too that wild species, unlike civilized man. do not have access to arti- 

 ficial heat nor can they put on extra clothing at will. This is particularly true of birds which 

 do not even grow a heavier coat of feathers. They must, therefore, rely to a much greater 

 degree on producing within their own Iiodios the added warmth necessary in cold weather. 



Production of body heat is dependent upon the proper functioning of the various internal 

 organs — in other words, the animal's physiology — as well as upon adequate shelter and food. 

 These vital processes are !iot static. Rather they undergo constant adjustment to changes in 

 the activity of the animal and the environment in which it lives, as well as in the amount and 

 quality of food eaten, the presence of disease and other influences. 



* Lone. W. H. (unpublinhrd) foiinj tlie frathcri n( 24 adul! ermine In nvrraRp 7 per cent nl llii- total iiiiti.il wfichl. 

 A fly William !I. Long, 



