1923] Atsatt: Behavior of the Leaf -nosed Snake 309 



later. The temperature of the air under the blue light varied from 

 30° to 28°, The snake crawled around actively, attempting to get 

 into the sand and trying the glass at the corners several times. Then 

 it was allowed to get out of the box and into strong sunlight on the 

 table. It moved into the shadow cast by the blue filter and traveled 

 along in the neighboring shadow cast by a book. Next, the snake was 

 put into a box of sand in which the temperature ranged from 26° to 

 27° under the blue filter. For the next fourteen minutes the animal 

 moved around trying to get out. When the blue filter was taken ofi!, 

 the temperature of the sand rose eight or nine degrees in twenty-five 

 minutes, while within one minute of taking off the blue light the snake 

 tried to burrow in the sand in the shaded portion. It kept for the 

 most part in the shade ; if it got into the sunshine, in a second it 

 quickened its rate of locomotion. It dug a hole by the side of a 

 small rock and crawled under and beyond it into the sand, where it 

 remained quiet. 



On April 16 this experiment was repeated, but with the tempera- 

 tures lower. The temperature of the sand under the blue filter varied 

 from 18° to 19.5° and of the air from 19° to 21°. During the time 

 of experimentation, from 3:46 to 4:35 p.m., the snake was in constant 

 activity. It wandered around trying to get out, especially at the 

 corners, or trying to bury its head in the sand. In general it kept 

 at the edge of the box either near the thermometer at the east end 

 or more often in the shadow in the west third of the box. Occasion- 

 ally it went diagonally across the sunny area. After two attempts 

 at digging a hole it partially coiled itself in the hole it had dug in 

 the southwest corner in the shade. 



On April 21 the blue filter was placed over a box of sand warmed 

 at one end to 42° and at the other to 24°. The snake itself had been 

 in sand at 36°, in the dark. Under the blue light it displayed great 

 activity and moved into the shaded end which happened to be the 

 cool end. After about six minutes of comparative quiet spent in the 

 shade, it began more rapid activity, and continued for twenty-five 

 minutes. It made attempts to burrow, to dig, and to get out over the 

 corner of the box. There was no apparent difference in the amount 

 of time spent in the cool and warm ends of the box, but most of the 

 time was spent in the shadow along the south and west sides of the 

 box. When the snake was put in cool sand of 24° in direct sunshine, 

 the same type of movement continued. When it was allowed to creep 

 over the edge of the box to the table it crawled into the shade cast 



