288 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1936 



upon the Panama specimen of the preceding year, though the lat- 

 ter represented a different subspecies. The animals so gorge them- 

 selves that their bodies become almost spherical. This gorging 

 consumes from 20 to 25 minutes. 



In some experiments with large fowls, weighing up to 8 pounds, 

 the bats were observed to be extremely cautious in their approach, 

 slowly stalking in a circle wide enough to keep out of reach of the 

 bird's bill. An action of that kind might readily kill a light-bodied 

 bat. After several circular maneuvers, an approach was made to 

 the fowl's feet, the bat feeling its way forward inch by inch, and 

 finally nibbling gently at the under surface of the toe. This ap- 

 peared to serve the purpose of getting the fowl accustomed to its 

 toe being touched. If the fowl made an abrupt move, the bat would 

 dart backward, then slowly stalk forward to resume its attack. 

 Whether any slight "shaving" of the tissue was taking place and a 

 salivary secretion was being applied by the tongue it was impossible 

 to determine, as the bats were too timid to bear extremely close 

 inspection. After these preliminaries, however, the mouth was 

 rather slowly opened as if to gage precisely the sweep of the in- 

 cisor teeth, and tlien there was a quick and positive bite. While it 

 has been customary to allege the utter painlessness of vampire bites, 

 in several instances where fowls were under observation, there was 

 a decided reaction of motion on the birds' part, showing that the bite 

 was sharply felt. If the fowl moved, the bat darted back, but im- 

 mediately returned to the wound, now freely bleeding. From this 

 point the bat continued its meal and the fowl paid no further 

 attention to it. 



PHYSIOLOGY 



Desmodus is no larger than the larger insectivorous bats. A par- 

 ticularly good female example of D. rotundus rotundus^ from Brazil, 

 shows a length of body of 4 inches and a wing spread of 13 inches. 



The incisor teeth are extremely sharp and have a curvature that 

 forms a scooplike mechanism. The incisors are well in advance of 

 the canines. The lower incisors are widely separated, forming a par- 

 tial channel for the darting motion of the tongue in taking up blood 

 from a wound. Examination of bites shows a craterlike wound. 

 The sharp upper canines, being set far behind the incisors, appear 

 to play little part in most wounds. 



Experiences of reliable observers point to a remarkable painlessness 

 of the average vampire bite. There are statements that victims knew 

 nothing of the attack, and would have remained ignorant of such 

 a happening had they not found blood stains the following morning. 

 An expedition from the University of Michigan in Santa Marta, 

 Colombia, may be cited (Ruthven, 1922) : 



