346 ANXUAL REPORT SMITHSONIAN INSTITUTION, 1925 



were scarcely able to move. We found centipedes rolled into motion- 

 less coils, spiders lying dormant in the interior of snail shells, ear- 

 wigs in a slu<j:jii^^h state with their antenna' thrust back along their 

 sides. Under some stones were numbers of dead insects, as though 

 many had sought concealment in the autunui and died during the 

 winter cold. 



Hibernation must be a valuable protection to the animals. At the 

 base camp I made an artificial burrow like that in which the pikas 

 are accustomed to hibernate. At a foot beneath the surface its tem- 

 perature was almost uniform. From 8 a. m. to 9 p. m. it remained 

 at 33° F., while during the same period the temperature of the air 

 varied through 19° F. Thus by burrowing the animals gain great 

 advantage. They escape extremes of temperature and find uniform 

 conditions. In winter they gain it even still more when they hiber- 

 nate in the soil under thick snow. The conditions under a stone are 

 also favorable for hibernation, though not to the same extent as a 

 burrow in the soil. At an altitude of 17,000 feet the temperature 

 beneath a stone varied through only 12° F. during the 24 hours. In 

 the same period the temperature of the air varied through 44° F. 

 Thus the beetles, the spiders, and many other creatures gain more 

 equable conditions by hibernating under stones. 



The hot springs of Tibet supply a place of refuge in which 

 animals can escape the cold. In one place we found these springs 

 bubbling through the soil and flowing away in warm streams. The 

 temperature of the water was 60° F. A varied life inhabited these 

 springs, chiefly Crustacea and different kinds of sliells. The only 

 snake from the Tibetan plateau that I know inhabits the hot springs. 

 In my original report on the fauna of the plateau mention was made 

 of small leeches found at a height of 16,000 feet. It was found, 

 however, on more careful examination, that these little animals 

 were in reality planarians. 



In the struggle for existence at these great altitudes many animals 

 are driven to extreme heights. It indicates how relentless is the 

 force of nature to spread into every habitable corner of the earth. 

 The wild sheep and mountain hares struggle up the ranges even to 

 the barren slopes at 17,000 feet. There is a little redstart which 

 places its nest at the same inhospitable height. We found grass- 

 hoppers at 18,000 feet, near the farthest limit of vegetable growth. 

 We frequently saw the magnificent lammergeyer soaring round the 

 mountain at 20,000 feet. We found bees, moths, and butterflies at 

 21,000 feet, spiders at 22,000 feet, choughs at the immense height of 

 27,000 feet. We found traces of a permanent animal existence far 

 above the Himalayan snow line and 4,000 feet above the last vege- 

 table growth. These were small spiders, and are the highest exist- 



