Activity and reproduction of Eptesicus brasiliensis (Chiroptera:Vespertilionidae) in the Rio de Janeiro State, Southeastern Brazil

The biology of Eptesicus brasiliensis (Desmarest 1819) was analyzed using data from 14 locations in Rio de Janeiro State, Southeastern Brazil. Eptesicus brasiliensis was in a variety of habitats, from sea level to higher locations, although never represented in high numbers of captures. Most of the captures occurred over water. Bats were captured between 24 min before sunset to 700 min after sunset and showed a bimodal pattern. Four captures were observed before sunset, comprising two pregnant, one lactating and one inactive females. Only eight animals were captured 360 min after sunset, five of which being females with palpable fetuses. Males with scrotal testicles were observed between the months of November and April. Pregnant females were observed from October to February and lactating females from November to January. The period of male maximum sexual activity coincided with 75% of the period of pregnant females. Out of all the captured pregnant females, five had one or two embryos. A female gave birth to two neonates with weights of 1.8 and 1.9 g, representing 30.8% of the maternal weight. Male synchronicity needs more accurate techniques to ensure the reproductive strategy.