Meeting Abstract

117-4  Thursday, Jan. 7 11:00  The Efficiency of Bounding Vampires HERMANSON, J.W.*; DZAL, Y.A.; ORR, T.J.; YORK, J.M.; CZENZE, Z.J.; PARSONS, S.; Cornell Univ., Ithaca; Univ. of British Columbia, Vancouver; Univ. of Massachusetts, Amherst; Univ. of British Columbia, Vancouver; University of Auckland; Queensland Univ. of Technology, Brisbane jwh6@cornell.edu

Vampire bats, Desmodus rotundus, maximize their feeding cycle of one meal per day by being efficient in stalking and acquiring their food. Riskin and Hermanson studied the running gait of D. rotundus and observed long stride lengths and decreased stride frequencies. We measured the gait of 14 D. rotundus maintained for up to 10 minutes on a treadmill at speeds ranging from 0.23 to 0.74 m/s, which spanned from walking to running gaits. Bats transitioned between gaits at about 0.40 m/s. There was no significant change in stride duration or frequency with an increase in speed. The switch to bounding gait reduces the need for an increase in stride frequency. We measured O₂ consumption and CO₂ production both before running, and 1 and 5 minutes after exercise, and found that O₂ consumption increased 1 minute and 5 minutes after exercise. CO₂ levels increased significantly from baseline to 1 minute after exercise, but tended back towards pre-exercise level after 5 minutes. We measured body temperatures prior to and immediately after exercise. Baseline temperatures were about 38° C and increased to as much as 41.7° C suggesting bats were not able to maintain their baseline body temperature while running with the wings folded. In summary, we studied the unique bounding gait of D. rotundus and observed an increase of metabolism about 1.5 times greater than pre-exercise levels. While some running terrestrial mammals increase metabolism 6-8 fold, the running gait of vampires appears to be more efficient because of its low stride frequency and the use of relatively long thoracic limbs.