HETEROTHERMY IN HOMEOTHERMS 



thermal sensations were not numbed but remained alert. Their toler- 

 ance of cold appears to be an active accomplishment and not the re- 

 sult of insensitivity. I think it is right to say that they are adapted to 

 cold, because their accurately developed reactions enable them to 

 achieve the simplicity and comfort that they seek by wearing light 

 clothing. 



Reactions of Eskimos' Hands to Cooling 



Since we are biologists we should look for adaptation as a f\mc- 

 tion of populations and not look merely in the samples of young men 

 whom we usually test. But it is hard enough to make observations on 

 vigorous young men when they are exposed to cold, and experimental 

 exposure to cold might appear to be cruel treatment of delicate wo- 

 men and frail children. Since 19 47 1 have of ten enjoyed the good com- 

 pany and been aided by the intelligent appreciation of arctic life of 

 the vigorous Nunamiut Eskimos who live by hunting caribou in the 

 mountains of arctic Alaska. While we were visiting with Simon Pan- 

 eak and his pleasant family at Anaktuvuk Pass last March, Keith knd 

 Jo Ann Miller and I were able to examine the reactions of a sample 

 of the population to cold. The men wear warm fur clothing while 

 traveling, hunting, and working. Their small children set out to play 

 in warm clothing, but in excited enjoyment of their strenuous sport 

 they may play for hours after they have lost their mitts and after 

 their disordered clothing becomes infiltrated with snow. It was no 

 problem to get them to sit outside in air temperatures just below 

 freezing with bare hands while we observed them from the comfort 

 of the sod house (Figs. 6-11). 



The hands of five Eskimo men and two young ladies remained a 

 little warmer than those of three white men and two ladies. I think it 

 is significant that the hands of the adult Eskimos showed marked re- 

 warming reactions earlier than the white people, for we had noticed 

 that when immersed in cold water the hands of Indian men at Old 

 Crow began to rewarm earlier than the hands of the white men whom 

 we tested there (Eisner, Nelms, and Irving, 1960). The tiny fingers 

 of the tough little Eskimoboys cooled rapidly and very quickly began 

 rewarming cycles which continued at short intervals as lively as 

 their play. The boys' hands were often colder than 10 C. 



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