Although information about colonies composition of the common vampire bat Desmodus rotundus (E. Geoffroy, 1810) are important to the Program of the population control of vampire bat, few studies on this were carried out in Brazil. Biological data of the D. rotundus colonies from São Paulo State were obtained in 1999 and 2000 and they are presented here. In general, the natural and the man-made roosts were not big in size and they varied in their structural aspects which have influenced the bat distribution within the roosts. The vampire bat colonies had 130 individuals in average, living in three roosting sites, and several lonely bats and small groups were also found disperse within the roost. The sex rate of colonies was 1 male: 1,37 female and the most of bats caught inside the roosts was adult (89%). Sexual size dimorphism was observed in forearm length and body mass, being females bigger than males. Most of adult males (87%) were sexual active, but 65,5% of adult females were not pregnant.
Behavior; bionomics; southeastern Brazil; vampire bats
