A single adult male resides in the vicinity of each female group and attempts to maintain his position and thus the ability to mate with the females. If the roost is within a hollow tree, this male is positioned near the top. Other males roost in groups nearby and attempt to displace the top male. They often are successful, and thus paternity varies within a social unit. Fighting between males is vicious.
Some females have a postpartum estrus and produce more than one litter per year.
The young are well developed at birth, and their eyes are open. While they first feed on regurgitated blood in their second month of life and can forage for blood themselves at 4 months, they are not completely weaned before 9-10 months. Sexual maturity seems to come at about the same time. The vampire bat long has been considered a threat both to people and to their domestic animals in Latin America. The main problem at present is the transmission of rabies from Desmodus to the cattle on which it feeds.