THE HIBERNATION OF ANIMALS. 



NATURE presents no greater or 

 more curious phenomenon than 

 the habit of certain animals to 

 conceal themselves and lie dor- 

 mant, in a lethargic sleep, for weeks 

 and months. It is known that in per- 

 fect hibernators the processes of nature 

 are interrupted during the period of 

 this long insensibility. Breathing is 

 nearly, and in some animals, entirely 

 suspended, and the temperature of the 

 blood even in the warmer blooded ani- 

 mals, falls so low that how life can be 

 maintained in them is a great mystery. 



A variety of Rocky Mountain ground 

 squirrels, when in perfect hibernation, 

 says an observer, has a temperature 

 only three degrees above freezing point 

 of water, and when taken from their 

 burrows are as rigid as if they were not 

 only dead, but frozen. But a few min- 

 utes in a warm room will show that 

 they are not only alive, but full of life. 



As to the suspension of breathing in 

 hibernators, the fact is proved suffi- 

 ciently in the instances of the raccoon 

 and the woodchuck. When they have 

 laid themselves away for the winter 

 sleep they roll themselves up comfort- 

 ably and press their noses in such a 

 position against their hinder parts that 

 it would be an absolute impossibility 

 for them to draw a breath. It is gen- 

 erally supposed that the bear rolls 

 itself up in this way and does not 

 breathe, but the holes melted in the 

 snow beneath which the animal fre- 

 quently stows itself, under a covering 

 of leaves, prove that it does breathe 

 while in its lethargy. 



The marmot family produces the 

 soundest winter sleepers. When the 

 marmot is in its peculiar state of hiber- 

 nation the electric spark will not rouse 

 it. The most noxious gases do not 

 affect it in the slightest. If its temper- 

 ature is raised above that at which the 

 animal breathed in its natural state it 

 will die almost immediately. 



Our own familiar wild animals, the 

 bear, the raccoon, and the woodchuck 

 — the so-called ground-hog — are classed 

 as perfect hibernators, because they 

 store no food for winter, but have 

 acquired or provided themselves with 



a thick, fatty secretion between the 

 skin and flesh, which, it is supposed, 

 supplies them with sustenance. xA-S a 

 matter of fact, although dormant ani- 

 mals absorb fat, it does not enter into 

 their digestive organs. Food intro- 

 duced into the stomach of a hibernat- 

 ing animal, or reptile, by force or 

 artificial means, will be found un- 

 digested at all stages of its lethargy, 

 for it invariably goes into its peculiar 

 state on an empty stomach. That is 

 one of the mysteries of the phenome- 

 non, not so great, however, as the fact 

 that bears and woodchucks produce 

 their young during their winter sleep. 

 The male bear is frequently roused 

 from his sleep and is found by the 

 woodsman roamingabout in mid-winter, 

 but they have never known, they say, 

 a female bear to be killed after the sea- 

 son for hibernation has set in. 



Squirrels are_ only partial hiberna- 

 tors, from the fact that they work all 

 summer and fall storing great quanti- 

 ties of food to supply them when hun- 

 ger wakes them up during the winter, 

 some of them, no doubt, spending very 

 little time in a lethargic sleep. 



The common land tortoise, no mat- 

 ter where it may be, and it is a vora- 

 cious feeder, goes to sleep in Novem- 

 ber and does not wake up again till 

 May, and that curious animal, the 

 hedgehog, goes to sleep as soon as the 

 weather gets cold and remains in un- 

 broken slumber six months. 



Bats, at the beginning of cold 

 weather, begin to huddle together in 

 bunches in hollow trees, dark corners 

 in deserted houses, and in caves and 

 crevices in the rocks. They gradually 

 lose all sensibility, and continue in a 

 comatose state until the return of gen- 

 uine warm weather. When you see the 

 first bat of the season fluttering at 

 nightfall you can be sure that warm 

 weather has come to stay. The little 

 hooks at the end of one of the joints of 

 each wing are, what the bat hangs itself 

 up by when it goes to sleep, whether 

 for a day or for months. When the 

 bats are clustering for hibernation one 

 of the number hangs itself up by its 

 hooks, head downward, and the others 



