How Animals Talk 



change of diet before he dens for his winter sleep, 

 is a question which does not concern us, since 

 nobody can answer it. In either case the deer 

 have felt, as surely as our most sensitive instru- 

 ments, not only the decreasing pressure of the air 

 but also its increasing moisture. 



That such sensitiveness is not of any one organ, 

 but rather of the whole body, becomes more evi- 

 dent when we study the lower orders fishes, for 

 example, which may winter under a dozen fathoms 

 of water and a two-foot blanket of ice, but which 

 nevertheless respond to the changing air currents 

 far above their heads. Once on a northern lake, 

 in March, I kept tabs on some trout for fourteen 

 consecutive days, and it seemed that they moved 

 from deep to shallow water or back again when- 

 ever the wind veered to the proper quarter. I had 

 a water-hole cut in the thick ice, and, finding a 

 trout under it one day, I kept a couple of lines with 

 minnows there constantly. The hole was in a 

 shallow place, over a sandy bottom, and by put- 

 ting my face to the opening, with a blanket over 

 my head to exclude the upper light, I could dimly 

 see the shadows move in from deep water. On 

 six scattering days, when the wind came light or 

 strong from the south, two of the days bringing 

 snow, the trout evidently moved shoreward, since 

 I caught them abundantly, as many as I needed 



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