ABSTRACT
The reproductive cycles of bats living in temperate zones are forced into a relatively short time span. As a result, in these bat populations breeding is highly synchronized and reproduction characterized by one birth period per year. Offspring of the common vampire bat, Desmodus rotundus, can be found throughout the whole year, a fact which was first noticed by De Verteuil and Urich in Trinidad and confirmed for other South American regions. In Costa Rica Turner found the highest number of pregnant females during the rainy season and discussed an influence of the hormonal status of the prey cattle on the sexual cycle of Desmodus. Mating occurs frequently with captive Desmodus. In Diphylla sperm heads are substantially broader and more rounded, and the attachment of the head is farther off center than in Desmodus and Diaemus. The cumulus cells of Desmodus resemble the granulosa cells as in most mammals.
