shinn] hibernation AMONG PLANTS AND ANIMALS 107 



take up their journey to warmer climates. Woodchuck roams 

 through the orchard earher in the afternoon and later in the 

 morning, waddling like a duck. Burro wers extend their quarters 

 and provide litter for the bed. Many insects, as plant-lice, change 

 their mode of reproduction. Other insects, males or drones, fiy out 

 to die or are killed and removed from the nest so that returning 

 spring may awaken only fertile females, the founders of new 

 colonies. 



In lakes and streams myriads of insects in immature stages 

 leave the cold surface waters and seek more favorable conditions 

 at lower depths. Frog and turtle and crawfish bury themselves 

 in the mud . Fish undertake their fall "run". In old ocean many 

 jellyfishes, their life work in one short summer done, decompose; 

 other delicate surface-floating forms, taking on a new and more 

 resistant guise, seem to disappear. The birds gather into noisy 

 flocks for their southward migration or for the winter pasturing 

 in some favorable spot where abound the concentrated foods of 

 nut and fruit, of e^gg and dormant pupa. The plant's heavy seed 

 coat in the animal is a double one of hair and fur or of feather and 

 down. External fats conserve whatever internal warmth there may 

 be and excess internal fat may be aggregated into definite fat 

 bodies, Corporo adiposa. 



The only definite calculation at hand which shows the preparation 

 for hibernation compares two animals of similar diet, the hiber- 

 nating striped spermophile or "gopher" and the non-hibernating 

 squirrel. In the first the protein of muscle amounts to 30%, in the 

 second to 20% ; that of the frog is even higher, 40%. Summer pulse 

 in the gopher is 200 ; winter pulse is 4 and each pulsation endures 

 four seconds ; amputation of a limb brings only a few oozing drops 

 of blood. His summer respiration is 50 but that of winter is 

 imperceptible; summer temperature is 105°and that of winter, 

 58°. In winter the blood is withdrawn from the chilled skin and 

 is congested in the thorax. Hibernation, then, requires a goodly 

 supply of stored food but the storehouse is only slowly drawn upon 

 during the long winter sleep. Probably much of the supply is for 

 the activity of early spring and the heavy drain of the little family. 



In a general way, hibernation is a characteristic response of 

 many temperate and frigid animals and of all such plants; it is 

 even characteristic of arctic man, who, for days on end, sleeps in 

 crowded hut of snow or turf and in his own enveloping fat. It is 



