282 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1936 



at the rate of about four darts a second. At the instant of pro- 

 trusion it was pinkish, but once in action it functioned so perfectly 

 that a pulsating ribbon of blood spanned the gap between the sur- 

 face of the fluid and the creature's lips. In 20 minutes nothing 

 remained but a red ring at the bottom of the dish. The bat's body 

 was so distended that it appeared spherical. She backed off from 

 the dish, appeared to squat, then leap, and her wings spread like 

 a flash. She left the floor and in a flying movement too quick for 

 the eye to follow hooked a hind claw overhead and hung, head down, 

 in her usual position of rest. Gorged and inverted, she preened 

 herself like a cat, stopping occasionally to peer out of the cage in 

 the light of the single, shielded lamp to which she had become 

 accustomed. 



Summarized, these observations appear to add much to the his- 

 tory of Desmodus. In less than half an hour it had been demon- 

 strated that the vampire can assume a walking gait as agile as a 

 4-legged animal; that the reason for its long thumb is its use as 

 a foot on the wing stalk; that it is not a blood-sucking creature 

 as has long been alleged ; that it can gorge itself prodigiously and 

 assume an inverted position to digest its meal. 



The problem of recording these actions on motion picture film 

 was at once considered. The outlook was doubtful. If the vampire 

 had been hesitant about performing up to that evening in the il- 

 lumination of a single, shielded light, it appeared that lights of 

 enough actinic power for photography, yet tolerable upon the bat, 

 would necessitate a slow introduction and increasing the strength 

 of the lamps. The observer's plan was to build up the illumination, 

 night after night, through a resistance coil, or dimmer. 



Two Aveeks were sjoent in gradually increasing the strength of 

 the light. Ultimately the bat tolerated three 500 watt bulbs, with 

 a reflector. The scenes were exposed on 35 mm pancromatic film. 

 The lens employed was a 4-inch Zeiss, with long light-cone. Re- 

 sults were clear and satisfactory and the greater number of the 

 illustrations accompanying this article are enlargements from the 

 motion-picture scenes. 



Since contentions as to new habits, based upon a single specimen, 

 are far more satisfactory if they are afterward substantiated by 

 observations of additional individuals, it was determined that field 

 observations should be continued and additional vampires obtained 

 during the summer of 1934. Meanwhile the junior author started 

 a search of the literature for observations other than the mere state- 

 ment that the vampire is a blood-sucking animal. This search, con- 

 ducted in the library of the University of Michigan, revealed an 

 interesting continuity of inferences concerning habits, and some 

 authentic observations. 



