IBVING 



would produce enough heat to make them uncomfortable in the sum- 

 mer and if this could modify their intake. Such an effect should not 

 bother them in winter. 



HANNON: We do not know, except that in the winter they have 

 heavy insulation. In the summer they do not. 



MORRISON: They can lie in the snow and dissipate more heat. 



HANNON: I believe Dr. Irving has made some measurements 

 on the amount of heat that huskies dissipate to the snow when they 

 are lying down"? 



MORRISON: Well, how much they can dissipate and how much 

 they do dissipate depends on whether they are in a heat dissipation 

 "posture" or not. 



HANNON: If dogs are lying in the snow dissipating very much 

 heat, a melting of the snow should be evident. This does not seem 

 to occur. 



IRVING: There is no melting. John Krog and I measured the 

 temperature under dogs by putting a grid of thermocouples under 

 the place where they slept. We found that the temperature at the 

 surface was not above freezing, and the snow did not melt although 

 it did become compressed. If the snow had melted, the fur would 

 have froze to the snow, and you never see any fur frozen in a place 

 where a normal animal has been bedded down in the snow. 



JOHANSEN: If I may switch back to the high temperatures now, 

 I think that we really need a lot more measurements. The only 

 really detailed study available is Asmussen and Nielsen's study 

 of athletes, which showed a rectal temperature of 41 C after long 

 track running. It may be surprising to you, but it is not to me, that 

 the husky, with its tremendous insulation, gets such a great in- 

 crease in temperature. 



IRVING: Have you obtained any evidence that he really develops 

 a better faculty for supporting a high body temperature? 



170 



