Close footage taken of a captive Diphylla ecaudata feeding on a chicken near the cloaca. Filmed in Mexico in December, 2007. Chicken was held upside down. This footage refutes an argument by Greenhall (1988) in his chapter on feeding behavior in the book "The Natural History of Vampire Bats" (Greenhall & Schmidt, 1988, CRC Press). He writes on pages 127-128:
"The actual biting by Diphylla has never been described...Because of the difference in head morphology of Desmodus when compared to Diphylla, it is reasonable to surmise that the feeding behavior would be completely different...In viewing the photographs of Diphylla, both front and profile, noticing the broad and flexible lips, and keeping in mind the features of Diphylla, I speculate: that if the bat covered a wound made in the cloacal area with its lips and mouth, it could make an effective seal and then apply suction. Diphylla could feed in the simple, uncomplicated manner of "Dracula" not possible for Desmodus and Diaemus."
This footage shows Diphylla ecaudata using typical licking behavior to obtain blood from the bite. The wound is itself notable in being a clean "slice" wound rather than a crater-like wound resulting from a typical Desmodus rotundus bite.
The still image shows the position in which the bat attaches itself, with feet clinging to the tail feathers.